You are right. "XTZ Spirit 2" front/rears depth is 5 inches. Center "XTZ Spirit 6" is deeper - 6 inches. Even at that, its the shallowest speaker set I could get. Thinner than that are either insanely expensive or have inferior sound. Even this 5.0 set costed me nearly 1.25 lakhs
I don't see the costs going down this year. Even next year when things simmer down, I think that the only difference will be that costs will stay the same and not go up. If you are interested, PM me, the dealer I bought it from offers best price for AVRs. I got my Denon 3700H for 1.13 lakh but prices have further increased since then.