That is an entirely different issue. GDPR is effectively an update of DPA 1998 that it replaces. Most is the same, definitions and scope are widened and modernised. A company that had implemented DPA(1998) was most of the way there for GDPR(2016). If you're going to get pedantic, DPA 1998 is one of the many implementations of EU's DPD 1995 as there is a fundamental difference between EU Regulation and EU Directive.

Clearly I am not calling GDPR (2016) a minor update of a subsequent law UK DPA (2018). That is UK's implementation of GDPR, which thanks to the stupidity that is Brexit may indeed have some issues interrelating with the EU. Probably the least of our issues, but still...

UK ICO's stance is fairly well known, but I don't think they can be held responsible for businesses that liquidate in the face of fine. That seems more likely to be an issue of UK company law.