If you have a good architecture and keep good code hygiene, then velocity is easy. Without that, everything will slow to a crawl.
That's a big "if" however - customers have a tendency to come up with requirements that aren't covered (or only covered in awkward ways) by the architecture you envisioned initially, while many of the well-architected parts will remain unused.
You will never get the chance of "customers requesting changes" if you never ship.
The company with the janky code that shipped will. And they will iterate and get better - as described by your process.
Why does good code imply never shipping?
Managers and Developers have different thresholds for “good enough to release”. The former are not the one on call for bugs or the one that get blamed for outage, but they are the ones that get praised when projects are completed quickly. Anything that’s past demo level is good for them.