This guy knows how to market and ship product. I've seen him pop up a few times on indiehackers.com and social media. His "brand" is super simple to understand, which helps gain followers. He knows marketing.
A lot of people who try to go from being a dev to entrepreneur focus entirely too much on the engineering side (I'm guilty of that) and think that what matters most is the product and how well it's made. We focus way too much on tools, processes, and forget that at the end of the day, we're trying to exchange useful products for money. Getting your product(s) out the door and telling people about it (and iterating) are way more important than what stack you use.
I'm a little disappointed by all the negativity here, but I suspect most of us are just jealous.