‘too many businesses and organisations are reluctant to use data – either because they don’t understand the rules or are afraid of inadvertently breaking them’ TBH I'm glad companies stay away from my data if they don't know how to get consent, store data securely, or even what those things mean.
Most of these companies wouldn't know how to make much use of the data anyway. My experience working with companies and analytics (even did an analytics startup some years back) is that they haven't a clue about how to actually use it and just heard that more data is somehow better. That to me sounds like they're most likely to sell the data, since they don't know how to use it themselves. Better these companies have…
As an example, let's say I want to launch a blogging platform. You need some basic tables (data) like User, Posts, Tags, etc. I'd consider this data the business needs for core business. Does there need to be some GDPR compliance thing?
Anecdotally a dumb app I built I was worried about EU visitors and just wanted to block them instead of figure it out (yea yea maybe that's not the right approach but I'm sure the sentiment is common).