Can't tell about Next.js but my conclusions on React are strictly opposite to yours, as someone with 8 years of exp with React, 15 years of exp in the industry, doing front, back and infra on a daily basis. A former teammate also told me last month that his new shop just rewrote their entire front codebase from Elm to React, because of how simple and fast it is to implement anything with React, and how easy it is to find good developers and well maintained packages for it.