Loyalty programs have always been travel’s most powerful retention tool — but the game is changing faster than most brands can keep up with. The credit card co-brand has long been the engine that funds loyalty ecosystems, but a new generation of challengers is rewriting the rules of what loyalty actually means and who gets to play. Bilt Rewards turned the humble rent payment into a travel currency. Suppliers have continually devalued their own loyalty currencies to the point of irrelevance. C...