I don't understand all the QQing it's definitely doable
I am a filthy casual and completely free to play. I've been playing for roughly a month and a half and do my dailies every night while watching TV.
I've never needed to buy any currency using real money and always keep some aside for emergency boosters.
So far I've not failed a single event girl and have cleared up to level 9000 in the main campaign, and collected Lupa, Finalmecia from Gatcha and Keira, Sabrina, Hari, Rabbi, Titania and Lyka from the current event.
I do agree that the game is heading in a pay to win direction even in my brief time playing.
All my girls only have rank 3 << bonuses and I cleared this using all of the available boosters at once with around a level 12500 skill and all crafts at about 240.