Headless CMS will be the future but for the technical expertise people. Right now, HCMS is not the day-to-day thing that usually people can manage, there is a long way to go with customization and flexibility. I have tested a few variations of WP headless but they are very basic, to be honest, also it does not support themes as well. So basically, have to code up for a theme. So I would say there is at least a good 5 years for a headless CMS to come up to the point where it is usable by almost all non-techie people. But, looking at how the open-source community not picking up the pace in headless space, is also worrisome — so the time could be even longer. There will be always a market for website builders even when headless CMS comes into a consumer model. Headless CMS is basically HTML output — so it won’t do dynamic functionalities (yet). Right now, Headless CMS is a specialized solution. Whereas website builders can be used by almost anyone. If I had the options, I would go headless CMS way, but that is not the case for everyone, in 5 years, Headless CMS may take a 5% share from Website builders — because headless CMS still will require servers that many people do not want to deal with.