And even if that succeeded you often end up with fear of change because the complicated architecture can't be touched.
It's really important to have the right balance here, but KISS and YAGNI are often easier to scale when you need it, than the reverse. If you don't have the mentality that the MVP must never be rewritten.
That, plus "they're probably going to fire us in a year anyway, who cares" thinking
And "we don't need to understand the business domain, let's just MVP", which they get away with because they would get accused of not being agile if they did boring stuff like trying to understand the business
I refer more to bigger off shore consultancy shops than individual freelancers
My company does exactly this. We build and maintain an open source project (SpiffWorkflow, for process automation) and help our clients build internal skills to deploy it and use it. No license fees or SAAS lockin - and no team of developers that walk out the door when things get difficult.