Getting a visa isn't so onerous is it? Compared with the hassle of upping your roots and moving your family?
When I was choosing where I'd go for university, the UK wouldn't have even made the shortlist if moving here was even slightly more inconvenient than just walking in. The only thing the UK had going for it is that I already knew the language. There are plenty of other places in Europe where skilled labour is in demand.
Let me ask you this, if the US or Canada offered you a job, would you refuse it as their requirement for a visa means they don't want you there?
Requiring a visa or a work permit would switch that around. It may expire and not be renewed for a formality. It certainly would make our live more miserable by introducing an extra element of uncertainty.
OP could just as well seek naturalization if hes actually spent his entire life there.
Being asked to leave your citizenship behind isn't just some paperwork, it's a very big blow to your identity. In my case, it would have almost no practical effect (I'm European either way), but it would be a huge issue.
It's kinda like marrying. You may claim that it's just paperwork (and I'm sure some people really feel that way), but I felt there was something more about it. Sure, I had been with my now-wife for eight years at that point, but being the act of marrying made it much more Serious (yes, capital S). If you've ever been married, maybe you can relate to that feeling.