I think the point is that if you create something for yourself and no one else, then you won't be a successful entrepreneur, because to succeed at that, you have to create something other people love and secretly, you want them to love you, not what you create.
And you agree with this point? I just like building things. I will always do this. However, the sheer joy of something i've built and someone likes using is a journey I am loving. I have this theory that if you build something that you can personally use, then you've built something worth while. Now, as far as wanting someone to love you, who doesn't want that? I certainly don't want to be hated. But I also don't want to compromise myself either.
I agree with his point and your point. I have done what you are doing: Build something I love. But remember, your customers are not you. When you start selling your invention, that thing that makes you happy, your customers may not be happy. If they aren't happy, you won't sell a lot of it.
The author of the blog post is saying, "If you don't care if your customers are happy with the product, you won't be a good entrepreneur." By good entrepreneur, he probably means sell a bunch of stuff.
Just liking to build things or just liking to build things for yourself is not enough to be a successful entrepreneur. Building a commercially viable product takes lots of iteration and design changes and polish that individuals don't need in product they use only for their own purposes.
Your theory is a good one. It's a theory I had 3 years ago and pursued and now I have something I love and my customers love. The problem with the theory is that you loving it is not enough for your customers to pay for it.
Personally, I like both (a) making things and (b) making other people happy. It's why I cook dinner for friends. It's why I develop products. I think, as humans, we all have some broken parts in us, and hopefully adding value to other people's lives can help us with them. For some of us adding value to other people's lives includes building products and organizations.