It's based on the platform. Nobody would've bat an eye at a Switch or PC game for an upfront cost, but asking 10$ for a mobile game was kinda unheard of. I think they misjudged the market response there.

I can't say I'm not biased here, I basically hate 95% of all the mobile games I ever tried, or at least stopped playing after an hour - so a 10$ purchase for me would simply never happen, because I don't like the platform. On the other hand I did do the "paid unlock" after trying it out for a few. (Ignore this if they had a demo, I never tried it, wasn't it iphone only?)