Unless you have a basis for saying something has objective existence, you have no basis for saying something has objective existence. I proposed the test, satisfactory demonstration. You don't have a test?You are literally willing to concede that until something is discovered that something doesn't exist.
It wasn't overnight, but yes, that's how truth works. Truth in such matters is our best opinion for the time being, the people best qualified to be satisfied with the demonstration. The Higgs boson wasn't real, its reality was not a truth, until the LHC produced the satisfactory demonstration; and after that, but at no time before, it was true.Just think of the Earth for example. For a long time everyone thought the Earth was flat as they had no reason to think otherwise (all their observations lended support to its flatness) yet after it was discovered with further, better obervations that the Earth was a globe (according to your theory) the flat Earth stopped existing and the globe was born.
That's true for us in 2018. Depending on where in the world you might be, it wasn't true until Eratosthenes or it still isn't true.It's only logical to say that the Earth was always a globe even back when noone knew its true shape and that the only thing that changed after its discovery was its epistemic status with respect to humanity.
So what's your test for whether something's true as at this date, or not?
And how do you tell whether something has objective existence or not?
And what makes you think truth can ever be absolute, so that what we know is true is THE truth forever?