If multistatic radar was deployed and operational, then how come the
US, NATO, France, UK, Japan, and Saudi Arabia invest so much
money in maintaining a "monostatic" AWACS fleet?

Why does the US, Europe, Asia, and especially India and Pakistan,
invest so much money in "monostatic" mobile radars?

That information alone should tell you how significant multistatic radar
has been integrated into defense systems. I can appreciate one transmitter,
multiple receivers, but using it to shoot down aircraft and track them
through the national airspace has not been so successful that very
expensive weapon systems have been rotating into the boneyard.

I think your either dreaming, or incorrectly extrapolating what you
read in Aviation Week, or Time magazine.