Some misconceptions here about Blu-Ray.
Firmware updates are to combat piracy. The Blu-Ray Disc Association from time to time will require newer discs to mandate a particular firmware to be present on a specific model of player as a way to force the customer to update. These firmware updates aren't on the disc and must be downloaded either directly or by downloading the firmware update to a USB drive and plugging it into a USB port on the player.
An annoyance, but non-existent updates are never mandated. So when the plug is pulled for support and the latest firmware release for Player A was say V3.6, there will never be a Blu-Ray video disc that mandates a newer level of firmware to be present on that player than V3.6. The only issue is if you one day can't access that firmware to upgrade a long out of production 2nd hand player that was on older firmware.
But thankfully obsolete patches and firmware are fairly widely distributed on the internet and updates are typically allowed via USB (Even on the PS3 you can update your PS3 firmware and what Sony terms your Blu-Ray "encryption key" via a firmware file on a thumb drive; Direct updating via the internet is just present for convenience). So hopefully it won't ever be a significant issue down the road (I have a pair of older dedicated players that ceased to receive updates years ago that still play my latest purchases from Warner Archive, Kino Lorber, etc. ).
Unsure how newer game consoles handle it, but USB updating is at least an option on PS4 as well and always seems to be a feature on dedicated Blu-Ray players. It wouldn't surprise me if updating via thumb drive is something Microsoft shied away from with the Xbox One with Sony following suit with the PS5, but with how tied to the internet these are in general, I suspect playing our Blu-Ray collection will be the least of our worries when the plug is eventually pulled years from now.
And as long as your firmware was up to date when the pull is plugged, Blu-Ray playback will probably be one of the most intact features for these platform's future offline life.