in fact this promise was once made by steven jobs, except that the phones at the time were not capable enough.
the question is not, what's the point of using web tech for underpowered phones, but the question is why do you expect me to cater to a minority market, and when do we reach the point that any device is powerful enough to handle web tech?
because that is where the future is going. native development is a stop gap to handle high performance requirements, but make no mistake, its days are counted. web development is the future that will replace all app development, whether we like it or not. even on the desktop, thanks to webassembly the browser is the future development target on any device out there. native apps will become a niche for only very specialized applications, and servers.