Longer answer: doing things in-house that are outside your core competencies and/or value creation model is a poor use of scarce resources (both capital and human—predominantly management bandwidth) and increases risk carried.
To give a concrete example: imagine you need to host your source code repository. You can pay for something like Bitbucket for $6/month/user and not have to worry about it. It’s a price that scales linearly with your team size and is a tiny fraction of their total cost.
Doing it in-house: you have to pay for hardware, storage, worry about backups, have somebody support it, have somebody manage the person that supports it, deal with users, find a solution to remote access, and so on. But all these miss the big cost—risk—what happens if the server dies or your office burns down? Nobody used to get fired for buying IBM, nobody now gets fired for buying a popular SaaS product.
You aren’t Google, at some point scale changes the equation, but that’s a rare spot to be in.