In summer 02 they bought Rio for £30m. The next highest fee signing in the Prem was us with Anelka at £13m, so by comparison for the market to be less competitive this window the next lowest signing after our "£100m" would have to be £43.3m. They've already spent £73m on Sancho, comparable to the actual £80m upfront on Grealish, and Chelsea are in for Lukaku at £90/£100m. For us to have the same comparable buying power as the rags had in 2002, we'd have to spend £168m on players without the Rags spending any more money after Sancho, and of course they bought Varane for £34m*(actually more like £50m).
That £30m is worth £50m today so is comparable to signing a Stones, the net on Dias etc. so the only CB truly splurged on in recent times was van Dijk...