I think it’s totally do able and even Epic has personal project Friday 
An interesting side effect is the more assets and resources that you collect from just the market place the clear it comes on how easy it would be to fork and recycle into other projects. Tappy Bird for example was done in a single day.
The Mixamo animation pack is another thing to look at as you can prove to yourself that you can quickly switch the art concept on a dime and work on two different movement systems at the same time. Once the Market Place is open I’ll give it a year before someone with software sense will will be able to make a AAA title game on their own. (or of at least say Two Brothers quality)