It makes no sense not to compete on the consumer side. The enterprise side has enormous barriers to entry, like a long sales cycle, RFPs, security audits etc. Office 365 simply offers more, plus with a familiar interface that doesn't require extra training for end-users.
Who is going to be championing Dropbox on the enterprise buyer's side? Employees that are satisfied consumers or the IT office that uses the same 4-5 vendors for everything?
I don't say you're right or wrong, cause I don't know. All I can say is that you cannot say "makes no sense" because it's been working OK for them so far. They have ~15M paying users and the number keeps growing (not at a very high pace but still steady growth). Their revenue is growing at a higher pace than expenses. Enterprise sales is not easy but they have been doing it for a while now. They also expand their product line to be a more complete solution for team productivity and collaboration. They have been doing a lot of mistakes on the way. They launched many products that failed. Their vision was lacking. But overall their numbers show it's a healthy company moving in the right direction. It's just not been growing in the pace everyone was thinking they would after their IPO.
Who is going to be championing Dropbox on the enterprise buyer's side? Employees that are satisfied consumers or the IT office that uses the same 4-5 vendors for everything?