Those who don't have a legit claim can also apply there to see if any countries have a need for their skills/abilities. That way, anyone past the border countries can be immediately processed as someone who has no legit claim/was trying to circumvent controls and be deported.
But that requires international co-operation and for us to fund it fairly, without threatening to pull support for political leverage. That's something many on the right have consistently demonstrated they are incapable of, or unwilling to do.
What and give up their Trump card of "throwing their toys out of the pram"
Exactly.
Macron's observation is critical here because it's a recognition of the underlying issue. The current migration can not be handled sensitively or successfully without it being grounded in international and cross-border co-operation. Brexit is the antithesis of that, and it is doomed to fail.
But then, it would be fair to argue that's precisely what they want. They don't want to solve immigration. They need it to be a bogeyman to cover for their other policies which no one in their right mind – unless stuck in a crab mentality – would vote for.
All that (sensible!) international cooperation you suggest could extend to countering the original reasons people decide to up sticks from all they know and No chance so long as aid budgets are cut and national interests come first (even within the EU!) mean such cooperation is unlikely
There would still be many economic migrants - of course. A world that is wired together where there are communities in every wealthy country will never lose those And not all problems driving poeple to leave home have a solution - but we could do better