Well, I'm a noob with OOTP, starting with OOTP 15 and I have only played historical, in fact that is what attracted me to the game - the incredible historical possibilities and depth. I don't follow MLB so current rosters don't hold much attraction... I couldn't even name all the expansion teams from the last 20 years.
Sure it's less flashy than playing current MLB, so it's not surprising really that historical players are a small minority, but it's an important minority given baseball's rich history. I think fans tend to know and care more about the history of baseball compared to other sports, with the possible exception of boxing. So having the historical possibilities built into the game with no additional fees is a sales point and sets OOTP apart.
I wasn't planning to update very quick to OOTP 17, but the inclusion of historical minors is something I can't resist, even if I need to start a new league to include them. I salute the team for focusing on that and am just blown away when I think of the insane amount of work that went into compiling that sort of database.
That being said, I also have a strong interest in the Atlantic league and I'm hoping historical schedules/rosters make it into the game at some point