This is actually one of the techniques I already use to speed up development time. The starter website is essentially a complete framework with all the tools (plugins) and settings in place so you are not starting from scratch every single time,
Develop Websites FAST: How to Shave HOURS Off Each Project with the Starter Site Method – Design Build Web
The faster you can build websites, the more money you’ll make: fact. What if you could shave hours (a full day, even?) off your development time? What if for each new website project you started building in just a few minutes? Wouldn’t it be nice to avoid the brain-sapping, time-consuming monotony of setting everything up first?