Whatever the reason, it's a killer for F2P. I was able to take reasonable actions to get the mythic 7 as a F2P when it was 75k but this event has been brutal and not fun. I've had to log in more often, and get less sleep, and I still may not make the mythic 7 despite all that effort.
I ask the devs to move it back to 75k. This is harming the game. It doesn't seem like a big deal, but it actually has a ripple effect on the late push for F2P to get the mythic.
I did not spend the 150 gems for that quest. You have to log in several times (10-15) a day to maximize your boss fights to get as many tokens / day as you can. The main problem is time. It also helps to have research combos ready at the start of the event to clear those first few quests so you're not waiting for them early.