This is excellent advice. There is a local company near me that has been working on their SaaS for almost 2 years now and still yet to launch. They started it on Angular 1 and are now re-factoring it on Angular 2 (or maybe 4 now). During this time they released a small open source Angular library but not even an alpha release of their own product. Keep in mind their product is not gear towards devs. They also hit every Angular conference they can and are always doing dev meetups. That is fine for after you launch and are making $$ but seems like a lot of wasted time and money when you have yet to release a product after 2 years.
During this same period, I launched 2 SaaS products on boring PHP 7 and Python for the backend and HTML, jQuery/intercooler.js for the front-end. Both profitable and growing.
I think sometimes devs don't realize the hardest parts of starting and growing a business have nothing to do with code or the tech stack you choose. Marketing, getting and retaining customers and everything else in between is way harder than writing code.