I think in about ten years, all the modulars will be MSRP $200. Heck, if Lego follows the CMF pricing trend, the modulars could all be $300 in the next five years. Lego's been reaching on price more and more. Inflation is just about zero in their major markets (EU and US), but Lego set prices are heading up fast while price per piece falls.
Anyway, I don't think we'll ever know why TH got chopped. Lego went right on producing the $200 ToO, $200 Simpsons House, $200 Red 5, the (ahem) $400 Death Star, and since TH left we've gotten the $200 Tumbler, $200 Slave 1, and $200 UCS Tie Fighter. Are modular buyers especially stingy and unwilling to pay $200? I somehow doubt it. After all, they're now happy to pay $550 for TH on eBay.