The reason PHP and other, "joke languages" are still in use is because business needs power businesses, not engineering wants. Plenty of businesses are still run on pen, paper, and custom spreadsheets because those things just work or work well enough. Could they do a better job or scale up more with a SaaS offering or two? Possibly, but why?

SaaS... the thing where you have to shutdown your business for the day because AWS us-east is down even though your application runs on Azure?