Oh but Uber itself is a pretty big and ambitious idea past the single sentence description. It also touches a basic need of transportation and is very ambitious.(trying to displace taxis everywhere) Due to the scale of the idea, both creating and building Uber is a hard task. (Mostly because at small scale you have stiff competition - so it does not make sense asy small scale.)

For comparison, you could back of envelope analyse the market impact of, say, automated 2D floor and garden planning with AI. It is possible to undercut in a week in implementation and in seconds by a single guy with marketing and connections. On the upside, it could be pivoted. The main drawback is that it also does not make sense at a local level. (Unlike the 3D printer repair which might.)