DQ XI already has a peak of 11,700 concurrent players online which is huge.
(https://steamcharts.com/app/742120). That's more than 10 time as much as DQ Heroes II. I also notice a trend where the playerbase keeps increasing, which means more and more people are buying the game via word of mouth that it's good and the port is great.
Analizing some other japanese games in this leaked list back in July with precise data:
https://arstechnica.com/gaming/2018/07/steam-data-leak-reveals-precise-player-count-for-thousands-of-games/
Nioh had a peak of 10,588 players, lower than DQ, and sold 357k copies up until July.
Tales of Berseria had a peak of 8,018 players. Sold 284k copies, lower than Nioh by a proportional margin.
Nier Automata had a peak of 23,813 players online. Went on to sell over 1 million copies. More than doubling Nioh in active players as well as in sales - we can see a pattern here.
It's very proportionate, as you can see. Going by this ratio, if DQ remains with a 11k active players peak, it should do around 400k in a year. That's pretty damn good, to be honest. And yeah, it's been on the global top seller list for the past 8 days or so.