But it would be better to gain that 30% of customers by not doing a shit job in the first place. This was the point of the presentation. Not doing a shit job doesn't take that much more effort.
A really important addition to this would be: it has to have been from the start.
The issue is that so many projects have not been designed with these ideas from the outset, that it indeed usually does take a mammoth amount of re-engineering and dev time to make these kinds of changes and optimizations after the fact.
Which is exactly why I cringe - often visibly - at any suggestion that a duct-tape-and-bubble-gum "MVP" is in any way/shape/form acceptable. That "prototype" will end up being the final product because dev teams have a tendency to accumulate technical debt like gangbusters.
To continue with the mediocre carpentry analogies floating around: a (competent) carpenter doesn't build a sturdy table by first building a shitty table and reinforcing it later.