It's not that straightforward. Because the capital generally appreciates too, the rental costs can be driven down below mortgage costs in some cases. But even without that, most mortgages require deposits, and to compare that against rental you also need to compare potential return from investing that deposit instead.

You can certainly profit by buying - I have profited substantially that way -, and buying serves as a hedge against outsize increases in rental costs, but there are also many situations where you can profit by renting.

Calling it out as a demonstration of frugality on the other hand is a bit odd.