I'm a level 99 player whose played for about 10 years. While I'm glad they simplified part 3, part 4 is still pretty much unattainable even with 14 Drink Machines. This game used to be fun, but this is the latest and most egregious example of the opposite of fun.
Quite simply, games are supposed to be fun, and if they're not then they're not worth playing.
I'm going to stop playing for a while, or possibly altogether. I might check in at some point in the future to see if the recipes/challenges are once again manageable. Or maybe I won't. It depends on whether I've found something better to do with my time.
Good luck to those of you who remain!