You are assuming that the flow of migrants continues at the same rate or more from the EU and forget that around half are non EU at the moment. It would appear that non EU migrants do come to the U.K.. EU net migration is falling. Many EU workers work in unskilled jobs. Who would fill those jobs? There is no guarantee that we have enough U.K. workers willing to pick fruit, work in hotels or in some conveyor belt type jobs.
When I was over to Bournemouth recently there were no Brits working in the Hotel that I was staying in ( or at least in jobs with contact to guests ). Tourism is booming in the U.K. because of the devalued „Brexit“ pound. We need to pull in this revenue and to do that we need enough staff. Blocking non skilled staff also creates problems. There was a huge jump in the number of Bulgarians and Romanians recently. That won’t keep happening indefinitely. Apart from anything else the pound has lost value making jobs in the U.K. a bit less attractive.
You presume I have an issue with migration, which I don't.
My point wasnt that migration numbers will continue at those level, it's a 'what if' question ? My point being if they did we have limited means of control, which is crazy.
We might need high levels of migration (skilled or unskilled) in future, especially with an angling population, we might have the capacity and the availability of services to cope with high levels of migration, but we happens if we don't ?
Unfortunately that's the issue with a the EU/ a lot policitians/those who voted remain, they assume that people who raise a concern or voted to leave don't like or see the benefits of migration, rather than addressing their concerns. If the EU had made one relatively minor (in my eyes) concession in relation to allowing at least some element of control, I believe remain would have won reasonably comfortably.
I have a greater issue with the EU which relates to my views on democracy and spent time in the lead up to the referendum reading up on past votes and treaties and didn't like what I saw. Neither do I like the bullying tactics post result. I had a sick/concerned feeling for days (probably weeks) post referendum, worrying about the impact of the result, however, their behaviour since, whilst not totally removing that worry has only re-enforced one of my main reasons for voting the way I did.