The UK is a special case and will not be "Europe" for long besides. Homogenisation of rules can take a while, especially when there is a cultural aversion to them. In this case I'd say there simply has not been enough time for this to happen.
The EU was never comparable to, say, America in terms of unity. Europe had too much history for it to work perfectly - every one was on what had been at some point some one else's land.
[0] https://europedirectemn.files.wordpress.com/2018/02/treaties...
You could say that about the UK - which lost a significant chunk last century and could well lose rather more this century.