I don't see what you mean. It's very easy to be GDPR compliant, just don't track your users. In fact, it's more work to be non-compliant than to be compliant.
Sure, protecting that information is more effort, but you should be doing that already, right? not just from a GDPR perspective but a business perspective too - if a competitor can get a list of all your clients and send them brochures with 10% discount on your prices, you'll close down pretty quick.
Link to this ever happening pre-GDPR?
https://www.acumenbusinesslaw.co.uk/2018/07/23/a-former-empl...
To them, I'd say "order with Amazon, then", but sadly that's a lot of lost clients.