Earlier quoted context omitted.
The UK is Europe's tech hub at this point (not the EU's), assuming by tech we mean the sort of tech discussed in the article. As the article notes, the VC ecosystem in the UK does actually exist and is spinning up, whereas in most of Europe it hardly exists. If you want something a bit more objective than the article's assertions, there is an attempt to calculate a ranking here: https://www.startupblink.com/blog/anal…
Well, I suspect a lot of the UK's startup stats are still connected to its universities. The page you linked shows London with a massive index lead over the EU. When you scroll down to the lists of notable companies, only ~10% of them are UK-based. The contrast of London to the rest of Britain is also much starker than for some other EU hubs. It's questionable whether the "startup hub seed" would have germinated had…
I didn't see the list of notable startups. There's a section about "noteworthy growth and decline" but it's not got a list. For the other lists it's not clear how they're ordered.
> It's questionable whether the "startup hub seed" would have germinated had the UK not been in the EU
So why didn't it germinate everywhere else in the EU to the same extent?
This seems like wishful thinking. The startup capital of the world is the USA, notably not in the EU. The EU has done many things that are clearly startup and tech-hostile, but it's hard to think of policies that help. The EU is structurally designed to make it easier for France to sell agricultural products and Germany to sell manufactured products, but one of the reasons the UK didn't benefit economically from membership is because the EU doesn't make it easier to sell services (and the UK not benefiting is under-reported but unambiguously the case, see the recent Parliamentary report on trade ratios post leaving [1]). Yet many tech startups are software-as-a-service, so lack of a single market for services really makes the EU irrelevant to the tech ecosystem.
> It's pretty clear that an island company faces more market hurdles than a continental one
It's not that clear. The British Empire was a global trade based empire long before the internet existed. It's only got easier since then.
[1] https://researchbriefings.files.parliament.uk/documents/CBP-... (read it carefully, civil service bias is apparent but the data is objective)