Yes, but why change the actual surface to hardcourt as opposed to laying out a different carpet?
The surface supplier for Kremlin Cup is the company run by Tarpischev's son. So it's all down to $$$.
Plus, they had to follow the general WTA trend. Men's tour is not the only one where capret tournaments were being killed off. It was even worse on the WTA -- not only were they replacing carpet with indoor hard wherever possible, they actually went on to destroy the whole indoor season to make a room for Asian events with no spectators but a shitload of money. Five years ago WTA had 3 Tier I and 5 Tier II indoor events, now it's only Paris Indoors and Moscow as Tier II, both with depleted fields. Men at least still have tournies like Rotterdam, Basel, Vienna, Bercy etc.