I dunno from what I understand Bethesda is still pretty good. I enjoyed my time with Skyrim and since then Fallout 4 is the only mess up (going by what people say as I haven't played it).
Regarding Bioware. They have only genuinely failed me twice: Jade Empire and Andromeda.
Regarding other maligned titles:
Dragon Age 2, I view as crap mostly based on reputation (I have only played a tiny bit of it).
Regarding Mass Effect 3, while I will agree that the ending sucked, it is overall one of my favorite games ever and the best of the Mass Effect games IMO.
Likewise, Dragon Age Inquisition is an underrated game. I was initially among the detractors but when I got past the whole MMO thing it turned out there was a chewier game at the heart of it.
Bioware is still one of my favorite developers, despite some mistakes. I loved Dragon Age Origins and Inquisition, and still liked DA2 despite all its issues. I also loved the Mass Effect trilogy, even though I thought the ending was a dud. Mass Effect Andromeda was their only major fuckup for me, and even that I had fun with... though I will probably never replay it.
My enjoyment of Bethesda's games is mainly just the TES series, all of which I had a blast playing. I didn't love either of their Fallout attempts, but I didn't think they were horrible.
Interesting.
For me it's personally that when I play an RPG, I wanna be invested in the tale of the characters that I am following, both in the mainline story and all the side stories that pop up, and that is where I consider these two studios the weakest.
Bethesda in their latest 4 games have honestly produced high profile duds in storytelling. The main quests in Oblivion, Skyrim, Fallout 3 and Fallout 4 have been some of the weakest and lacklustre stories among RPGs I've heard. And it doesn't get better with their sidequests, how they treat the lore of Fallout in their games (a ghoul surviving in a fridge for hundreds of years still irks me, not to mention how they wrote The Enclave, the Brotherhood of Steel etc.) They have the weakest writing team for being such a prominent RPG making studio. I can't seriously recall much except the stuff that really stood out in how much I thought it was just absolutely stupid (the thief guild quest in Skyrim having basically
one mission of actual thieving).
The same goes for Bioware. DA2 was overall a boring story despite them having all the groundworks for a pretty good one (a story centralized a city amidst a turmoil of hate between magic and non-magic users), not to mention the cheap look of the game, the weird detractions of art (that old lady dragon who suddenly turns out in super cleavage and giant hair horns in DA2) and more. DA:I had just a boring story with boring antagonist that wasn't the antagonist but I thought was the antagonist but have been told that wasn't so now I know not what the fuck was going on in there. And oh dear god I wanted to strangle some of the characters. Mass Effect 3 messed up just not the ending (which was an awful way of tying up a beloved series) but tons of plot threads from earlier Mass Effect games (the mystery of dark energy, what was happening with the star on the planet Tali was on in ME2 and much more). ME:A I don't have to go through at all it's just self-explanatory why that one fell on it's face.
I can see why people still like these two studios and it's fine, but personally they have just become, honestly, quite awful at writing their games which is a major important aspect of RPGs for me. When I spend so much time as a RPG demands of me, I want the story to be damn good or interesting. It's why I personally praise the shit out of The Witcher 3, especially Hearts of Stone which has one of the best antagonists, characters and stories of RPGs of all time. It's why I wish Bethesda would pull their head out of their ass and get Obsidian on making Fallout: New Francisco or something as they made the better of all 3 3D Fallouts (by freakin' miles).