If you are an adtech company who's primary business was selling personal information of users, then yes, of course GDPR will have had a big impact. Google has put a lot of effort into being GDPR compliant, so I'd assume a lot of busineses switched away from smaller competitors for that reason.

I run a small SaaS business, which doesn't do anything ethically questional with user data, and becoming compliant involved:

- writing a document on GDPR compliance

- changing a few settings so IPs aren't logged or are at least anonymised

- verifying log files aren't kept longer than needed and don't contain personal information that isn't needed

I don't even need a popup asking for users to give permission to store personal information, because I'm not doing anything that needs that.