Spacetime is both a way of thinking and an accurate description of reality. Reality acts as though spacetime is a real thing, to an excruciating level of accuracy. The spacetime model was adapted because that is how reality is seen to behave. Maybe not the last word, but the latest and most accurate word we have for the last 100 years or so. Any alternative will have to do better than that, I just don't see that happening yet, not even close.
Grumpy![]()
It's also rather incredible, that such well supported theories such as the BB, SR/GR are all inexorably linked and dependent on each other.
With the further discovery of evidence from double star systems and investigations into a trinary system, further certainty has been added and probably will be further added to.