I've been thinking about this a bit recently as have had similar doing OLD. Lots of messages without me responding, then when I eventually do sometimes after a few weeks or months lots of texts at the beginning, a few meets, then after a few meets maybe sleep together after a few of the dates, then get the gut feeling they are backing off, and then the gut feeling is true. No drama just fade away. So it's not like a quick one night stand or something.
What I've noticed is it happens when I finally, after weeks or months of them doing the chasing, start to initiate meeting, that they seem to lose interest. You would think that they'd get fed up of having to chase all the time and like it to be reciprocated, but the opposite seems to be the case. So maybe they like the chase or are afraid of intimacy or commitment.
Obviously not all guys, just these ones.
So it seems whether you wait to sleep with them, it makes little difference if they are this type. Just means it takes you longer to find out, and you've possibly had more time to build a connection. And also it's difficult to tell if they are this type, as if they are any good at it they know what to say, apart from the obvious future faking and red flags is hard to tell.if they are not this type, and it's meant to be, it won't really matter when you slept with them or how much you both texted and so on.
So I guess maybe have no expectation, make sure you're not future faking yourself, and if it goes from being happy for both of you to message whenever you feel like it, to second guessing yourself if its OK to message and getting headwrecked waiting for them to message, just forget and move on.
Often they are doing nothing wrong, neither of you owes the other anything though a bit of courtesy would be nice, and see each meet as a chance to try something out for a while and see if it works and if not ok, rather than seeing everything as having to move in a linear way to a relationship.
Don't want to be too soft, but also don't want to be too hardened. It's a difficult one alright, but maybe just adjust expectations not of how you want to be treated, but of how it may turn out.