A big contributing factor is that buying English players reduces the risk of a flop import. Well known that most foreign players may take a season or two to "blend in" with the demands of the English game. Many never make it at all. Buying a local player who already grew up with the game reduces the risk significantly, so clubs are willing to pay additional fees on top of that.

Kinda like why it's cheaper to buy new houses that are still under construction, as opposed to 2nd-hand houses.

Comparisons like that, unless adjusted for inflation (especially for the English league), is an inaccurate basis for comparison. It's like comparing today's RM4 bihun sup with our parent's RM0.50 back in the 60s.

Seems like a bargain. I pay as much for a nasi briyani lunch!