Maybe you could still do an RTS, but cut it down to the bare bones of what it needs to have.
Look at a game like Rymdkapsel. It's an RTS, but it cuts a ton of complexity out of the gameplay. By doing that, and focusing on some simple but fun mechanics, and a very simple art style, you've got an RTS that a small team or a lone programmer could implement.
Rymdkapsel cost $4 and they've got at least 10,000 downloads on Android and who knows on iOS so that means they've probably cleared north of $50k to maybe over $100k.
Absolutely, that's the exact genre I'd want to target. The RTS world is way too baroque, I love the minimalists.
The problem is that even a simple RTS has some brutal challenges - pathfinding is hard, and if you want to go multiplayer you have to find a way to get lockstep logic (in C#/Unity this means doing all your simulation math using custom fixed-point numbers and using lookup arrays for all your trigonometry) - that and you need unit-AI.
