That would be the exact benefit of a Steam like system - as a small developer you wouldn't have to maintain a web site and an e-store, you'd just sell distribution rights to the Online VST store.
As far as "too much work" goes, no reward without risk. If this is going to be a business venture then there's going to be some work involved in making initial business deals, building infrastructure, and so forth.
As has been mentioned, two distribution hubs are doing well right now: Steam, and the (Mac) App Store. Neither of them handle music plugins well, even if the App Store does do music applications to some extent. Right now Apple takes a 30% cut, I'm willing to guess that Steam takes a similar amount or a little less.