If big parties like Microsoft and Google back out of this market because of lack of customers, why wouldn't a relatively small/new party like owncloud not back out/disappear if business isn't as expected? You'd be bitten by a mouse instead of either the cat or the dog...
You run ownCloud on your own web server, (or in the web space your ISP gives you), it's a set of PHP scripts - I tried it on my XAMPP server and accessing it via WebDAV was very
slow, (possibly due to my ADSL rate but still, boring old FTP is so much faster).
So it doesn't really matter what happens to any other player in the market - it's your cloud server on your hardware.
From what I understand, GetFreeCloud and OwnCube are just two providers that use ownCloud and provide free accounts - so not really unrelated Deo