If Excel is as popular as everyone says it is, why don't we see more of the javascript addins? Excel as a platform makes sense to me. If I'm in Excel where all

If Excel is as popular as everyone says it is, why don't we see more of the javascript addins? Excel as a platform makes sense to me. If I'm in Excel where all my data is, I want to import more external data or publish data externally etc. Makes sense to do it from inside Excel no?