There's a consistent strain of conflation of this issue in all the GDPR threads, along the lines of "well, if you can't comply with the GDPR, you must be a evil company selling my data to bad people for bad reasons!"
You don't have to be doing anything shady with data for the GDPR to be a threat to you and your business. You can be collecting a bare minimum of data that you only use with the purest of intentions and still be in violation of the law and subject to its penalties.
Just asking for an email that will literally be used for nothing but to send a registration confirmation - you know, to sign up users, the same way we've been doing forever - puts you in its compliance crosshairs. You're now legally liable for a whole raft of additional compliance measures that probably necessitate paying a lawyer a decent chunk of change to make sure you're above board with. Your "MVP" has now expanded from "here's a simple idea I cranked out this weekend" to "here's a simple idea and a legal contract and audit trails that prove consent and an obligation to exfil data from my database on demand in perpetuity and data portability endpoints and data exchange contracts with every API provider I use and my database has to be encrypted at rest and highly redundant and I have to set up regular vulnerability scans and if I want to back up my database to a non-EU datacenter I have to obtain consent from all my users first and a bunch of additional requirements that possibly make it illegal to not age out my Apache access logs and why am I doing this at all again?"
GDPR significantly increases the friction for moving new ideas from concept to product, even if there is absolutely zero nefarious happening in the product. If it only made life hard on the people engaged in shady practices, there'd be a lot less concern over it, but that's just not the case. It doesn't just punish the misuse of data, it punishes the lack of proactive compliance to a set of criteria which are frankly beyond many hobbyists.
Some see this as a good thing. But I think that it's also fair to guess that it's going to cause otherwise good and benign ideas, products, and even entire companies to die on the vine as a result.