1) There's a finite number of satellites in known orbits that can take a finite number of images per day. If you know where they are you can do a certain amount of masking what you're doing. 2) So far most of what we've seen Ukraine do has been defensive and defense is always easier; you're closer to your supply lines, you know the area, you know where your fallback positions are, and generally you need significantly fewer people to do it successfully. The ratio of offensive vs defensive numbers to guarantee success have been pretty static for millennia. Yes, Ukraine has excellent intel and good artillery now, but they're still at a major disadvantage in terms of pure numbers and armored vehicles, and if they over extend that disadvantage can turn really quickly. Not saying that will happen, but it's a concern of mine.