Google uses lots of non-Google solutions for many things —just imagine all the facilities stuff. But so does any software company, including Microsoft and Amazon.
That said, you can hire people for any purpose (specific roles) and you can build what you want. It’s more a question of whether it’s worth it to build such solutions, after all you have a main line of business to tend to. That’s to say even Google and Apple have so called “boring “ roles and there are lots of people who don’t see it that way and want to work doing those things.
Actually lot of the facilities stuff is inhouse too - floor plans (not just the seat map but actual floor drawings that include physical infrastructure); the ticketing system for maintenance; work hour tracking for contractors; probably lot more that I'm forgetting.
But yes your point stands, sometimes it just makes more sense to use an existing product.
The floor plan tool isn't really in house. It's just an extension of the industry standard real estate management platform they use Tririga (https://www.ibm.com/products/tririga) ... in the same way that go/teams in just an custom visualization of a standard employee directory.
You might be surprised how much of what runs Google (Anaplan, for example, for XWS) is fairly industry standard.
Given the low expected profit margin, a CRM solution at Google would likely come from a 20% project (or rather, the equivalent thing these days since last I checked 20% is basically dead as a formal concept). Nobody expected GMail to blow up the way it did, for example; it happened because some Googlers decided they could probably do a web-client-fronted mail client with a Google search engine attached to it and if they did it'd be really cool.
But even with their, what, 180,000 people these days, I think it's entirely possible nobody is as excited about CRM as Paul Buchheit was about email services.
That said, you can hire people for any purpose (specific roles) and you can build what you want. It’s more a question of whether it’s worth it to build such solutions, after all you have a main line of business to tend to. That’s to say even Google and Apple have so called “boring “ roles and there are lots of people who don’t see it that way and want to work doing those things.