I think that devs must reconsider price increment for 5* star or money gain for it.
For example Ankyo.
4* - 2500 per hour. 5* - 2900 per hour. Cost - 12.3 mln and a huge amount of panties.
With about 10 hrs of gathering per day we got 4k per day and must spend 3075 days or 8.5 years to recover only money for increase.
And a more years for panties.


And this girl is only 13th in the list. 5* Abrael, for exampe, needs 37k affection or 15 mln for pantsu only.