No, Unity allows commercial uses either for free in some circumstances, or very, very cheap, so long as your annual revenue is less than $2M.

That makes it a no-brainer to use--you pay little or no licensing fees until your game takes off. Unity makes their money off the unpredictable winners, while gifting a nearly free product to the hobbyist and startup ecosystem.

Wolfram Engine is more like the Epic Games (Unreal Engine) model: free to download and play around with, but steep licensing costs before you ship anything. No way to quickly iterate and try things, only paying up when an experiment works out.

UE4's pricing model is a lot like Unity's pricing model nowadays as far as I can tell.

Yes, they changed after Unity are their lunch.