1. Convince the WordPress/enterprise crowd to switch over, both by touting the genuine benefits of static sites (security, scalability, TTFB performance, etc.) and by riding the Cool Kid Front-End Stack hype train.
2. Lock them in with an overly-complicated framework and build pipeline that requires organizations invest a lot of resources into switching. (Gatsby gets most of this for free by building on top of the Cool Kid Stack's nine-thousand-package NPM lasagna.)
3. Sell their captive audience expensive solutions to problems they wouldn't have with other frameworks. (See e.g. another commentor's discussion of incremental builds.)
This strategy might not contribute much to society, but neither do a lot of other startups--what matters to investors is that it'll probably make them a lot of money, assuming they execute it correctly.