Another possible reason - they may well have little choice! Lists of top ranked universities are generally dominated by the US/UK. In this list the highest ranked German institution is at number 30: https://www.timeshighereducation.com/world-university-rankin... It's always going to be hard to charge the same as a competitor when your product is inferior.
But what matters is how much of an improvement does an ivy league mean to a student compared to going to an average ranked university. Turns out it makes no difference. In some cases it actually makes your grades worse. E.g. if you are at the lower tier of a ivy, then it will kill your self esteem and motivation being around so many smart people, that studies show you will perform worse.
Ivy's are like useless luxury products, like a Gucci bag. It is for show off. No wonder asians are so obsessed with university rankings. They are also obsessed with luxury products. That is because those are societies obsessed about showing status and accomplishments.
If OTOH you don't care about superfluous things you don't need an ivy. I've seen how going for Ivy stuff can screw up people. Being around all these bright people, can create an insane expectation on yourself, and if you don't live up to that afterwards, it can haunt you for the rest of your life. Many people would have simply been happier individuals if they dropped the Ivy's altogether.