I'm saying that if today there is one caretaker for one retiree, but tomorrow there's one caretaker for 3 retirees then caretaker tomorrow can easily demand a lot higher pay than today - he'll work for the highest bidder. Compound interest gains can be offset by this inflation. Similar localized inflationary pressures can be seen in SV where there is limited supply of houses and there are many highly paid specialists who generate demand for those houses.

Now translate demand for housing to demand for services, and low supply of houses into low supply of workers providing those services. Everyone around you is using compound interest, so relative to each other you have similar purchasing power to them. Now you compete with the same people for those services. It's the relative power that really decides whether you can afford the services or not. If the workers don't have to compete with each other then you'll spend all that nice compound interest chasing them.