It may have been (co-)responsible for its downfall,
Well that's certainly part of it.
People don't realize how Sega has improved during the last years, after the restructuring, and has been outputting quality games one after another. Games have a higher finish level and are translated in more languages than before.
All their latest efforts look very good to me, and I am talking about the Sega stuff, not about Atlus who are doing there own things. Sega however has been outputting and overseeing quality games from all sizes.
Sonic Mania was awesome, great support to a small team of passionate developers.
Dragon's Trap Remake, same thing here, the game was fantastic, and their work on Streets of Rage 4 has already gathered approval from fans and is shaping up nicely.
Monster Boy, Sega simply proposed some publishing support I think, but it was again a quality game.
Sonic Forces reviewed poorly because a 3D Sonic can't review well, but the game is actually a lot of fun, has a high level of finish, and was one of the only AAA third party games to get released on Switch at the same time. I played the game one Xbox One X and it was awesome.
Sonic Team Racing is pretty comparable, well polished and fun.
Valkyria Chronicles 4 is one the best games this gen, and is a love letter to Sega fans.
The MegaDrive Mini, and asking M2 to work on it, again good choices aimed towards quality, and the selection of games blasts away all other Minis out there.
Great BC effort on Xbox as well.
Sakura Wars making a come back, I personally like what I have seen so far.
Panzer Dragoon, I am pretty sure that Sega will keep a close look at this.
PSO2 finally coming West, that's pretty huge.
All the stuff made by Yakuza Studio I don't give a fuck about, but probably some guys find that this is representative of Sega and of good quality ? Can't say.
They made surveys in past years to ask for the games we wanted to see, and they actually have been checking the list one game after another.
The Sega FES event dedicated for fans.
They have been building great foundations going forward, the good games are already here so just buy them and play them, otherwise nothing can happen, and it will be the exact same situation as before.