A common counterpoint when people bring up rules issues, is the notion of "hey its your game, play as you want". And for a good portion of people, that's an option.
Recently I've been given the opportunity to DM games at a local "beer and games" kind of place. Its similar to AL, a group of players show up, and off you go....though the DMs do get to run their own stuff, you don't have to run modules.
So in this scenario....sure I can spend valuable time and effort trying to put my houserules in the game...and a little more time convincing maybe 1-2 people who don't want those houserules....and a little more time reminding people of the houserules during the game, because I'm sure some people will naturally forget when its their first (and maybe only) session with me.
But lets be honest....time at the table is precious ESPECIALLY in these kinds of scenarios....and its just not worth it. So...the official rules it will be.
Adventure's League is the same way, while DMs have some flexibility... there is in fact an "official" way to play, and AL DMs are going to be following it.
So at the end of the day, the official rules do matter for a portion of the RP world. More than ever, the idea of going to Dnd events as compared is to a standard dnd group is becoming a thing....and with it, the burden (or benefit) the official rules carry. So yes...I do think the rules debates and errata and rules updates matter, because sometimes thats all you got.