"Lack of ads" problem is not a bug.
After a few tests I found out that there is now a daily limit on the amount of ads you can watch overall. The limit is 5. FIVE. No matter what you do with those ads: get resources from the shop, revive or double the resources you recieve from the run, they all count to the limit. All you have to do is to balance it out: 1 ad for 5 crystals from the shop, 1 ad on doubled resources and the remaining 3 on revives.
I'm not sending this message to either "support" nor "ideas" because I will bet my arm and leg that the devs have done that on purpose. And for an obvious reason.
To everyone who tells that they get no ads on the next day, I have a theory for that: ad limit refreshes at 2pm by GMT +3 timezone.