As I stated above, patches and updates to make a game work better aren't needed. Super Castlevania 4 has slowdown, Mega Man X has slowdown, many games on past consoles have slowdown, bugs, etc. Games on future consoles do as well, but the games, just like on past consoles, are perfectly playable without any updates. There are even same games which are more than likely going to get complete editions, which I myself wait for the release of those versions.
Aside from Destiny, Warhammer Vermintide, and a few online only shooters or MOBA games, there's really not as many games that require an online connection as you think, except to play online multiplayer. Diablo, Victor Vran, and the like, are playable offline in couche co op. Diablo 3 has a ton of content from day one, it does have patches that have added more content, but they just add newly constructed areas. They additionally have patches that change the sets and add three additional item slots for legendary skills, however, it's not minor changes in the game, and essentially completely change how the game works. So the day one version of Diablo 3 Ultimate Evil Edition is just a different game altogether as the patched version. Same with Payday 2, they updated the way that you do your character builds so it's honestly completely different than the base version of the game. Now yes, Payday 2 The Big Score includes 45 different missions while there is DLC released later that brings it up to 58 missions, but 45 missions is a pretty extensive amount of content, it's just the game is regularly being updated.
Now you did mention, certain games that require online to play with other people, and as I stated, these games would be unplayable multiplayer without online. Examples. Grand Theft Auto San Andreas had multiplayer and it wasn't split screen, the screen panned back the further the players got away from each other. Realistically though, it's pretty unplayable. But, how about The Legend of Zelda Ocarina of Time, how was the multiplayer there? How was the multiplayer for Brave Fencer Musashi, etc?
Demon's Souls though is pretty much The Legend of Zelda Ocarina of Time when it comes to similar and more refined gameplay. Just the gameplay part is more Zelda, not puzzles, etc. As at its core, Demon's Souls is really just King's Field in 3D with an targeting system, a dodge mechanic, and a bit more depth in gameplay. As questioned above, how is Ocarina of Time's multiplayer though? That's right, there isn't any. So the online multiplayer gameplay is yes, for a limited time and after the servers shut down it'll be gone for good. The single player game is able to be finished solo and it's not really that difficult. Same thing with the Dark Souls games and Bloodborne, except those games are even easier with the addition of AI allies that you can summon to assist. The online multiplayer is really only just PvP or to get help to progress. The games are still 20+ hours worth of content otherwise, and that's only for one playthrough with one of the weapons. If you like to replay the game with multiple different builds and set ups, then it'll take several times that amount. Bloodborne to be proficient with every weapon without just grinding to make an all powerful character, there's the strength bloodtinge build, the skill bloodtinge build, the pure bloodtinge build, the arcane build, the strength build, the skill build, quality build, and then all sorts of medium variations of those builds.
One Way Heroics has an online feature. It's pretty pointless to be honest. It's the first person who gets to one end and kills the enemy player. It's really just a novelty. However, as a rogue-like game in the traditional fashion, examples being Rogue, Fatal Labyrinth, or Shiren the Wanderer as examples, Mystery Chronicles One Way Heroics plays completely different from its predecessors. In the predecessors you usually got to different dungeons and then find steps to go up or down the dungeon to completion. In One Way Heroics, you're in a procedurally generated world map, so it's more like an adventure across the land, escaping from the darkness engulfing everything behind you. Same exact concept, different way to play the game and different difficulties, different objectives, different last bosses, etc. Chocobo's Dungeon 2 is the only game of this type that I know has local multiplayer, and the thing is, is the multiplayer is more or less broken. You essentially move once and the enemies move once. In Chocobo Dungeon 2, the player controlling Chocobo can move once, and then the second player can move freely, attack once, then still move freely without the enemies being able to make a move, essentially making you an unstoppable killing machine able to cheat the system. I'm sure you can understand why it's never been implemented as a co op game again.
So another question is, when was the last time you've played Resident Evil co op? Not since PS3, huh? Infact, like I said in a previous post PS3 and PS4 actually does split screen co op with the Resident Evil 5/6 games. Just a smaller resolution size per player as the games wouldn't run otherwise. They also play at 60fps on PS4(RE5 only with boost mode,) or 30fps on PS3 while in multiplayer.
Just to amuse you, out of all the PS4 games I own, not including racers, fighting games, sports games, etc, I am going to list the amount of games in my collection that include local co-op(PS4 only.) 22 games, again, not including any of the above that include LOCAL CO-OP, no online required. On the PS2, I have 21 and that's including each collection I own once(Sega Genesis Collection, etc) and Xenosaga because XenoCard. I even included Armored Core 2 and 3 and both expansions despite only having versus, while including Last Raven because it has co op. I didn't give that benefit to any PS4 game I own. Additionally, I didn't include any digital games that I own that have local co-op either. Games like Spelunky or Skulls of the Shogun for instance. Despite having them on my console, I don't consider them part of my collection. So 1/8th of both my PS4 and PS2 collection includes local co-op, more if you consider the fighting games, racers, and sports games that include it by default(including wrestling games as fighting.)
So yeah, I have a lot of games that include online multiplayer, but they still have a lot of OFFLINE ONLY single player content. and there's still 22 other games I own that don't fit in the obvious local multiplayer criteria on top of that I still can play local multiplayer, on top of all the other racing, fighting, and sports games I may or may not own on the PS4(just fighting honestly.)