A Lieberma wrote:
They would if the tower had no radar.

Ok, makes sense on the radar services being terminated, but the IFR
clearance still applies for airspace seperation?

IFR would be then cancelled once wheels touch ground???

At a towered airport without radar, you are still IFR until your wheels
touch the ground (assuming you don't cancel on your own). IFR separation
doesn't require radar contact. It doesn't even require radio contact.
Both of those just make it possible to apply more efficient methods of
achieving the required separation.