I came across a metacritic page that had performance ranked by publisher and it actually was pretty interesting to see where Sega stacked up. Their methodology in these ranks are 1) Average metacritic score 2) Percentage of games with over a 75 metacritic ("good games") 3) Percentage of games with a metacritic score 49 or under ("bad games") 4) Percentage of games that are over 90 metacritic (a "great" title). I linked the page of each year before the ranking. Also, anything from Atlus counts in these scores as well, since they're owned by Sega.
There are probably some flaws in this methodology that seem to affect exclusives and first-party games, but it's still kind of fun to look through. Obviously it's not the "be all end all" and it does seem like a company can be penalized pretty badly for a dud, even if they have a huge hit. But anyways:
2019 - Ranked 19th (though they consolidated the rankings this year so there's no difference between high and mid level publishers due to a year of lower release output)
2018 - Ranked 2nd
2017 - Ranked 3rd
2016 - Ranked 2nd (in the mid-level category due to a lower output of releases)
2015 - Ranked 1st (though a commentary from metacritic stated that they had a bunch of 3DS ports of old games and the only home console release was Tembo)
Of course metacritic doesn't always translate 1:1 to sales success and Sega hasn't really had a big hit in a while, just a few moderate hits. However, at least this does look like Sega has improved the quality bar a bit (I looked back a few years and their metacritic for many of those years was in the high 60's, while they're mid to high 70's in the list above). To be fair, I haven't looked deeply into what was released in those years and it's possible there's a bunch of PC ports, re-releases and the sort mixed in there.
Obviously, they still need a few more big hits (easier said than done!). I hope they find a few more opportunities to truly invest in creating a AAA console and PC title. Hopefully PSO2 gives them a nice income stream and stability to take a few more risks.