The crucial element is who you are writing for. I really don't think it makes a (decisive) difference whether a non-fictional book is written by a Kafka-like talent or just somebody who really knows how to cook/garden/lifecoach or whatever you are looking for. The difference between good and not so good is not the elegance of the wording, but the results derived from the book.

Real literary talent (or other artsy ones like taking photos) is only necessary in the sharply defined niche of fiction or art in general. There, you need talent to succeed and often artists don't even succeed if they have plenty of talent. But if you don't have talent at all, you won't go there in the first place - or leave it after trying and realizing you're not the one.

That's why: I really don't think the density of artistic talent is 1% or even less, on the contrary it must be quite high. At least over time, mediocrity is always filtered out. I agree on that with @everittdmickey. The market fixes that problem. This even counts for cheap throw away products of the popular culture. Those may be corporate artists, but they still have to bring a lot of talent and self-discipline to make it in the business.

Or are you just "dabbling" in this, for fun?

Aren't most users doing just that??