If you look at the price we pay for military equipment, then it’s not hard to see why. You can buy a simple bolt, but it can cost 10 times more than the same item used at home., because it’s made to military specifications.
I once saw a Mig 21 up close. I would describe it as ‘agricultural’ but it did the job.
You don’t need to spend lots of money if you don’t expect it to come back…
Plus, you don’t need to spend the sort of money an F35 costs, when you can get 10 aircraft that can do a the job. Sure it won’t be as good, but when you don’t care about lives, losing say 8 of your fleet compared to one of ours, means that they are likely to come out on top.
Plus I very much doubt that the Russians are handicapped by H&S or PC policies.