Microsoft explains why Edge has so few extensions
 

You can’t get the wood to build it these days

A year after Microsoft allowed extensions to appear on its Edge browser there are only 70 extensions available.

Now Vole has explained that it is "building a thoughtfully curated ecosystem," citing concern over quality and a fear of diminishing the user experience

What most people in the industry would describe as “slow as an asthmatic ant with a heavy load of shopping” Vole is trying to convince us is actually a "purposefully metered approach" to new extensions.

http://fudzilla.com/news/44623-micro...few-extensions