In my opinion, you lose out where transferrable skills are concerned.

You become a platform or product expert, which can effect your career in some ways.

I've seen this in situations where products from companies such as Salesforce are concerned.

I didn't want to become a Salesforce platform expert, I wanted to be able to pick the right tool for the job, regardless, and saw heavy investment into a single platform as a disadvantage both for the organisation as well as myself and our engineers.