I can pretty much guarantee that the cost of creating an offsite backup is trivial compared to the budget used to collect and analyze those data. I can’t read Russian anymore and it’s probably not published in a discoverable way, but I’m going to offer up the possibility that the sat network, research scientist teams, sys admins, and everything else that goes into the portion of the Russian government’s budget for this work wouldn’t have even seen that as a rounding error. I’ve worked with US government budgets and I know how tight fisted committees can be, and while the USG isn’t Google in terms of writing checks for tech, and while the Russians are probably an order of magnitude or two poorer than our budgets, it’s still be a no brainer in terms of costs. Either they just didn’t think of it (which I’ve seen far more times than I can tell you about) or it got eliminated as a line item by some bureaucrats who don’t understand cost/benefit analysis (which we’ve all also seen), it wasn’t truly a cost thing. Compared to the price associated with sat launches and data analysis, $10-$20k/ month for data retention is nothing.

Also, I sort of suspect that these were dual use systems. When you’re talking about the sensing tech they’re using, there are the very obvious and direct intel applications.