The point that things need to be "dumbed down" for casuals also ignores the fact that 5e is the most popular version of the game. It's a system that has already been proven to attract new players and keep them. It doesn't need simplifying to attract folks. It just needs a good tutorial. There are certainly issues that could be brushed up and improved but there's no way Larian is found any of this for the sake of casuals. Respeccing is a pretty standard inclusion in these games and you don't need to do it justbfor min-maxing. Someone might start a game as a rangers thinking they'll really like it, but then ten or more hours in realize they dont like the way it plays. So now they can change to something else and their time isn't wiped out. Simple.
Maybe casual players benefit, but Larian just want people to make stupid builds and do meme stuff. They never needed any of this. Blaming casual players for wanting this is diverting the point. Larian isn't doing anything Larian doesn't want to do.
The sad thing here is that dumbing down seems to be coming from Wizards of the Coast who are currently working to finalize the rules for the next generation of D&D releasing this year and I absolutely believe they want greatly simplify and remove a lot of the difficulty from D&D to make it more appealing to casuals. The initial changes they proposed where: only players can crit and natural 20 rolls guaranteed success no matter the task difficulty or even the player could even reach the required roll with a nat 20. As far as I understand these ideas were scrapped after backlash but it give you a general idea of where their head is at when crafting the next handbook. I believe the awfully butchered multiclass system in BG3 is also their idea as well.