It is also unbelievably customizable, with one click plugins that even your grandma can add, and practically anything you can wish for already built for you. It's also extremely familiar to practically every salesperson or management out there.
Basically Salesforce is to CRM what Wordpress is to CMS - the easiest one for non-technical people to use.
The trouble is that the other 25% of the functionally that doesn't fit into the Salesforce mold is hard to come by. Partly due to platform limitions. Mostly because developing on Salesforce is littered with pitfalls and requires intimate knowledge of how the platform works. Most "developers" out there are business analysts/admin who after writing a simple trigger were transitioned into a developer role. I very rarely run into other people with CS background.
Ha ha I actually had to work with it 6 months ago at a late stage startup.. What they needed was a simple apex trigger.. it took 30 min to write on a demo account.
.. but it took us a week to find out we couldn't do it because of the version of SF that we had, and an upgrade would 6x the cost of their monthly licensing cost.
It was a really bizarre dev experience. Really crappy errors!