If this scheme even gets off the ground (still doubtful?) it'll be interesting to see how it plays out. Some migrants are saying they'll stay put in France.
As others have touched on before, France and UK are wealthy countries. Long ago, if we'd wanted to (the governments I mean) there could have been a more (much more) concerted effort to stop folk coming across. They could have thrown more money at it for a period of time to put folk off attempting the crossing.
I confess to not reading in-depth about this over the years, however France has always seemed wishy washy on this, probably happy enough to see them leaving French shores. Even years ago when we all saw the footage of migrants running at lorries at Calais, often in daylight, and trying to get into/onto/under the lorries, why the f**k wasn't more done to stop them?
Specifically on the way governments have handled this, it stinks.