I'd be more concerned with oil breaking down into carcinogens at 450F+ temperatures, than with tin. Tin doesn't come into contact with food long enough to give you a harmful dose. Unless you like chewing on your cookware or something.
Popularity is a terrible way to measure quality. Most commercial kitchens are extremely price sensitive, and most newly opened restaurants don't last even 3 years, so there's huge pressure to use the cheapest stuff that will do the job even if it doesn't last... hence the cheap aluminum that eventually warps or loosens rivets. High end restaurants sometimes have bigger budgets though.
"There are 123 million households in the USA, how many have Ferraris?" See how that argument fails? It doesn't disprove that Ferraris are high performance cars.
That said, I agree copper isn't for everyone.