I would be required to log in at least a few hours/day to earn the daily login rewards, then spend two hours to grind dailies on my main, then another one-two hours to grind dailies on my alts to funnel mains. Throwing in one to two more hours if I have weeklies or events to deal with. Yeah, it is like 4-5 hours/day to have meaningful progression. Playing other games? Hah, perish the thought.
Hmm, I think Destiny 2 may be a Korean MMORPG...