This is not a strong argument. You can easily build a React Native (not that I think this is the right approach) application with most of the base JavaScript code and cutting the cost. If you have the right knowledgeable team. The PWAs still needs enough work to make them function as expected and deployed. Making software overall is very challenging. I

have fixed all kinds of software, and in my experience is customers wanting to pay for very little with gigantic expectations with a tall orders of wants. Small software firms bend over backwards to support these customers, and I have heard this double the cost. If they really wanted they could use Flutter to develop it all, also I am not a fan of it after working with it on a couple of projects.