To clarify, this has already helped me to ship features to my customers quickly. I actually spend little time working on the stack. Last time I touched the infrastructure components was probably a few weeks ago.
Panelbear was originally built and launched in a weekend ($5/mo DO instance with SQLite), and I've been working on it for the past 3 months. I have been releasing a new feature every week. That is, in addition to my full-time job, so most of the time we're talking about 2 hours per day tops.
I'd also like to clarify that I am not suggesting this stack should be used by other solo founder SaaS. I actually advice against it in my post :)
I just wanted to share my stack, as it has worked really well in my case, and I thought it'd be interesting material for discussion.