I agree with the sentiment on robustness. Unfortunately, as Spock once said, it is always easier to destroy than to create. Space is VERY expensive. Most satellite cost millions if not a billion dollars to build and launch. It takes very little to disable them from the ground if you have an adversary with the inclination to do so.
Space will never (or at least in my lifetime and probably the life time of my children) be populated to the point where the reluctance to press a button that exists for nuclear deterrence is present. So we can spend Trillions (that’s what it would cost) to have all our space assets armor plated, or we can stay in our budget and work all the cost, schedule, and performance trades to get best bang for the buck, and try to use other forms of influence (economic and political power) to shape the environment so that we don’t have to spend the treasury on space battleships that are obsolete shortly after they are launched.
Congress wont approve the trillions (and arguably shouldn’t), so the reality is we figure out the best way we can afford to deal with it.
That's the crux of the problem on land and sea too. It took 250 million dollars to repair the USS Cole from $250 worth of explosives. The land war costs are also quite asymmetric.
So we can spend Trillions (that’s what it would cost) to have all our space assets armor plated
Many are already going to be destroyed by inevitable solar flares and others are armor plated to some extent against such threats. But they key is in the sentence of yours I quoted above, the satellites that cost a billion dollars have been "obsolete" for decades, and we just don't want to admit it. As for spending trillions, that's unlikely. That calculation comes from spending a billion dollars on a satellite, it's obsolete.