Firstly, when there is mounting evidence the other side of the MAD balance equation is growing increasingly unhinged and insane, breaking MAD becomes the only sane response.
Secondly, it’s for this precise reason that I am saying both sides are laying the foundations needed by massively increasing orbital lift capabilities and not actively putting significant pieces in position yet. The idea is that once you give the go ahead, you will deploy your network faster than opfor can respond, and once you do seize the literal high ground, you have to be ruthless in exploiting it to basically enforce an orbital no-fly zone where anything heading to orbit that doesn’t have your prior permission to do so is immediately engaged and destroyed before it can breach the atmosphere.
Thirdly, your idea is only a viable counter if Star Wars is LEO only. In this day and age, it has zero need to be.
My feel is that the Chinese manned moon mission will eventually (longer timeline) results in a moon base that can be militarized in relatively short period of time if needed.
From the moon the Earth is orbitally locked. No deep space exploration is possible without going past the moon guard gate.
It is easy to intercept something from the Earth on the Moon than the other way round, because it takes much less to lift off from the moon than the Earth, and also you only have to travel 10% of the distance between them before the Earth's gravity works in your favour, versus the 90% of the distance other way round.
In the case where two major powers block each other from launching from Earth, the one with a working station on Moon can still launch towards Earth and also towards deep space. The one with a working moon station can keep everyone else in a zoo, really.
The advantages are so great the Chinese leadership will surely not ignore the implications and put in long period, continuous investment and work towards this goal.