Interesting that some of the top paid mobile games were from Steam. Is volume that low now on mobile games that being successful on Stream is a ticket to success on mobile? I do know gaming on Facebook has mostly dried up to more reasonable levels - for a while it seemed every friend one had on Facebook was playing games on Facebook.
I made one runner that was worth $0.99 cents for sure using Unity Free 4.6.1, the Infinite Runner Kit Pro, and various art work from the asset store. I didn’t write a line of code but did have to get some bugs fixed and alter some materials and textures which I know not much about.
Despite the fuss about non-originality if you use assets from the asset store, especially art wise, fact is, unless you own famous IP - one zombie character is like another and one anime character is pretty much like another. It’s a non-factor, especially since you can do a bit of texture altering rather easy. I looked in the last 2 days on App Annie and it’s easy to see the 3D art is Poser or DAZ or stock and looks good when presented correctly. Although many manage not to do so. Same with the 2D art. You don’t have to browse through many games to recognize the same art styles over and over.
Besides all that: the biggest games I’ve see at Apps Annie are using a style I’ve thought is, well, not very good or interesting at all (e.g. Clash of the Clans) or far too busy (e.g. Candy Crush Saga). It seems those were the styles used in the late 80s when I decided to stop playing video games. It’s pretty clear these games are about keeping fingers busy more than strategy or fun.
There are runner games from Sega (Sonic the Hedgehog) and Zynga (licensed Looney Tunes characters) that are good but I’ll be straight up with you - you can do the same yourself easily minus the pre-owned intellectual property and preferential treatment companies like Zynga and Sega get in product placement. So don’t feel bad if you fail. And Unity’s come a long way to make it so easy and work with enough CPU/GPU power.
I messed up in naming my game though - unfortunately the search engines for Amazon and Google Play to my surprise put far more weight to keywords in the game title then in the keyword section or description. 
Nevertheless I changed it in a couple of days to free well because although it was fun enough and not annoying with begging for IAPs or advertising it’s really just the foundation of the game I want to make and so in that sense was a good learning experience that I can use to expand to create a game that’s more original.
So 2 downloads for me - one download from a friend for his boy and another I don’t know. I myself haven’t actually downloaded but did do a genre search based on ‘christmas games’ and it showed up on page 31 despite being days old. Sorry bubba, no one gets a fair chance like that. If you change the sort from ‘Relevance’ to ‘New & Popular’ makes the search much less relevant as that just brings up the pre-existing IPs and already established titles with release dates truthfully a non-factor. And this on Amazon a less popular app & game store. On Google Play in 5 pages of listings and no way to sort by date of release or any other way my game doesn’t even show up. A post to Facebook on my personal page would have gotten 2 more downloads had I released to iOS by friends
children. It’s not insulting - these are adults with busy lives.
No advertising and I can truthfully say I got about what I expected with regards to downloads. It’s the listings and lack of available sort criteria that were cripplingly stupid and I can’t take credit for that. Look, if I ain’t going to wade through pages of listing to find my own game you can bet Joe Cool ain’t going to either.
If you checked out Apps Annie for the various app stores the past week you’ll see a surge in popularity for non-gaming apps like LinkedIn, Facebook, & Pandora. Fact is the expensive tablets & phones go to the earners in the household. Children get the hand-me-downs and cheap HW. Trouble is Unity doesn’t really work “almost easily” well on mobile until you get the duo & quad core CPUs and Android 4.4. Sorry folks - grownups with $800 iPads & Androids are not going to spend a lot of time searching for games. Most games I see are targeted to teenage boys.
So in summary just a heads up at what to expect on average so learn modeling and programming and enjoy them - just don’t expect to get rich. If you want to be business-like stay on Unity Free and target in the asset store very
carefully for your needs.
So make your runner & release to Steam if you get the votes or whatever they do. Realize though a lot of the voting is rigged.