Reliant on EU or reliant on big business? I can only comment that as someone with practical experience of exporting in and outside eu, from SMEs before and after europe was supposedly open for business, EU made that harder not easier.
As you notice such as Dyson as worldwide exporter is also a brexiteer. One problem big business has is EU can get you in their crosshairs. They made yet another risible decision in Dysons case to limit the power of vaccuum motors (a direct attack on Dyson by vested German interests) And that is one of the problems with EU:The laws originate behind closed doors from unelected officials as a result of shady deals.No transparency at all. No democratic accountability. Bills deliberately made so big, they cannot be addressed line by line, take it all or leave it. Although the entire commission resigned one year for shameful behaviour, they have taken care not to get caught ever since by wiping their fingerprints first.