Salesforce, the core database/CRUD bit of it if you ignore all the stuff they've purchased and tacked-on in the last few years, is essentially 'Access in the cloud', in terms of the sorts of things you can do and the ease with which you can do it, and how far you can stretch it before it starts to get cumbersome. And yes, they are making a killing.

edit: And if that sounds easy, imagine how you would go about upgrading and patching and extending your access-like cloud platform twice a year without any significant breakage of any of your customers varied and extensive customisations, and without any significant downtime, and keep that up for 20 years. Thats the thing that Salesforce are good at, and not many people appreciate how difficult it is.