In the UK a consultant with a moderate amount of experience and a GDPR Practitioner qualification can make between £500 and £800 a day in the City. That kind of work is largely going to be working as part of a team to survey the policy and process landscape of the organisation and suggest/make changes in accordance with the changes in the law.

But with regards to your point about having a law degree - I'm not sure where you're based but a qualified solicitor with a specialism in cyber law and data protection here in the UK will be set for a while. The GDPR enforcement date is a cash cow for consultants, but for lawyers this is just the beginning.

Edit: After seeing what freehunter posted at the same time as me - If you don't want to go through the hassle of becoming a qualified solicitor, then compliance is definitely a way to go. GDPR sets out a requirement for organisations to employ 'Data Protection Officers' so if compliance/risk management is of interest to you then the compliance ladder is pretty solid.