Product definitely matters to a degree, but being able to sell people on it (ie. convince someone they need it) is a more important skill. That's obviously an insanely broad generalization, but so is me saying lots of people can write an app.

You could argue that in a lot of domains you barely even need an app at all that requires more than wiring up google sheets to zapier or some such if you can cleverly package it up and target the right audience with it.

SaaS products are merely an exercise in problem solving for people/businesses and there's a lot of ways you can usually solve these sorts of problems without needing to be super technical with it. At that point your bottleneck will always end up being acquiring and converting traffic.

Your product has to work and solve a real need. It isn't that hard to figure out how to create an app. Communicating how that product creates value for customers, marketing it and doing all of the rest of the grunt work is the hard, difficult bit.