In my experience, a great startup business idea is one with 1, or better yet, 2 or even all three of these characteristics:
You have some sort of defensible intellectual property, like a process, a patent, data, expertise or a product.
By defensible, I mean you can defend it from competitors copying, reverse engineering or getting around it.
And, your IP creates a significant enough differentiation to your target customers that they want to buy your product and not direct or substitute competitors. They are captive to you and only you.
Unique Distribution Channel
You have a way to market and distribute your product that no other or few competitors can take advantage of.
The best example is your own subscriber list, whether its email, Youtube, podcast, or other social channels.
This is what I advocate to all companies.
Develop a product with such great product-market fit that consumers think…”WOW”.