I can't see nations going forward making the investment in nuclear weapons unless they've already been making big investments. Look at NK, they've made investments in nuclear weapons as well as cyberwarfare. I'm sure the investment in cyberwarfare has been much, much smaller and they already hacked into Sony, reduced them to doing paper payroll for awhile, and released a bunch of compromising information. Sadly, the response from the US wasn't very serious. Unlike nuclear, the response has to be asymmetric because they don't have much of a network infrastructure to attack.
I just don't see what to invest in for a Space Force. Anyone looking to attack something like GPS would either use something like ground base lasers, software/network hacks, or traditional projectiles. Anything developed by the US would either be obsolete by the time its needed or get sold to adversaries and used right back at us.
Weapons can be an endless pit of development and the US is not a conquering nation. Let's say we could sustain an economy and develop the first nuclear weapons while everyone else is using spears; what was the opportunity cost? What's the value if it's only used for defense?
Outside of defense I know a large military and weapons help in having influence, but so does having a stable and large economy--the later moreso.
Nuclear weapons were developed out of a competition for survival. The people involved knew even in the hands of the Allied forces it was extremely dangerous. You're arguing we should invest in a Space Force because someone else might do it in the future.
I just don't see what to invest in for a Space Force. Anyone looking to attack something like GPS would either use something like ground base lasers, software/network hacks, or traditional projectiles. Anything developed by the US would either be obsolete by the time its needed or get sold to adversaries and used right back at us.