The bottom line is that Apple knows how to sell products to consumers, and Microsoft doesn'tI disagree. Apple isn't selling a product to consumers, they're telling consumers, "Hey guys, by the way, Apple stuff just got a lot better. You're going to like the new way it works. Come check it out." iCloud is "the new way to store and access your content."
Apple knows they're in the business of selling Apple stuff, and iCloud is an improvement to that stuff rather than something separate. The fact that iCloud is a "product" is incidental and only matters to people who are used to thinking in those terms: stock analysts, MBA school marketers, shareholders, etc. To consumers, needing another "product" to do exactly the same things they've always been doing is a nuisance. Another complication? Fuck that. I like what I've got. I don't need them ramming another product down my throat. Apple's on their wavelength: they just want people to keep using Apple products and they want more people to switch. This is all about making existing products work better. Honestly, it would be more attractive to consumers if the this new non-product had no name at all, but Apple had to cater a little bit to all the journalists and analysts and bloggers who need a product name so they can talk about it. So Apple gave it a name that isn't catchy and only means something to people who follow technology trends.
I don't think Microsoft's slowness is just incompetence, though. There's also an issue of trust. Microsoft can't just roll out a cloud service and a whole bunch of cloud-enabled software to desktop users and expect them to use it. Who would trust Microsoft? Apple is just a company and shouldn't be considered trustworthy from a consumer's point of view, but it is regarded with trust and affection by a large number of users. Besides, if jack-booted thugs arrived on my doorstep as a result of something I stored in Apple's iCloud, it would probably be the Fashion Police coming to take me to a gulag for frumpy people (which I'm convinced is Apple's intended endgame.) Not only is Microsoft trusted less by its users, Microsoft wants enterprise customers as much as or more than individual consumers, and the number of businesses who won't trust Microsoft because they see themselves in competition with Microsoft or its business partners (or in violation of Microsoft software licensing terms) is pretty big. Microsoft needs a more complicated solution with better security and probably a productized cloud storage platform so users can manage their own cloud servers if they don't trust Microsoft. Apple is concentrating on consumers and has a loyal customer base that is willing to trust them with storage, so it's no wonder they've found it easier to make the jump.