I think it's possible find a useful middle-ground between consulting and product building, in the pg "do things that don't scale" sense. As the article also points out you can kill a second bird with the same stone, which is self-funding via the consulting.

And then ideally via the consulting you find a niche(s), build your own processes & tooling for your niche to deliver value to clients, and then can product-ize once you actually understand the space and the market, who the customers will be and how to reach them, because you're already doing it via the consulting and just need to scale up.

It also serves as a sanity check that you're actually building something that has value, because you prove it to yourself via invoices for your work rather than investment in an idea.