Native apps do network downloads of comparable or even bigger size too. I do not see how this can be an argument in SPA vs MPA decision making. „Rich client“-server architectures existed long before SPA became a thing and on much slower networks, so pretty much every problem modern SPAs face, from UX to performance to change management, was already solved by someone. Isn’t it actually ignorance of JS frontend community which has reinvented many wheels in rather ugly way, that causes the trouble?