I look for a "social friction" moat. If an idea can be executed entirely from behind a keyboard, the competition is infinite. But if it requires me to sweat, do meatspace socializing, and actually walk into a physical building to hand people a solution, competition drops to near zero.
The literal application of "do things that don't scale."
Beyond that, I look for ROI besides wealth. Even if it doesn't blow up in popularity will it still improve my life if just a few adopt it/appreciate it?
Do you know what "startup" means? A restaurant business isn't a startup. A consultancy isn't a startup. The whole point is to do something that does scale.
VCs won't invest in something that doesn't scale, and therefore angels and incubators/accelerators won't either, if they have any sense.
The software scales just fine, the initial user acquisition doesn't. That's literally the premise of the PG essay I quoted.
But thanks for the pedantic dictionary check on what a VC will fund. Super helpful contribution to a conversation about whether an idea is actually useful to human beings. Not all of us are building just to beg for angel money.