Why manufacturers does not producing variable sweep wing in our current scenario?
This was, as you are likely aware, the swing-wing was a major design element in the 1960s. Everything from the F-111 to the B-1 to the 2707 used them.

The design does have the advantages claimed for it, notably the better performance over a wider performance envelope. But the weight was a killer - not directly (although that may be the case in the 2707) but in relative terms.

Invariably what happened was that other parts of the system were improving too, engines, avionics, etc. At some point the performance improvement of the swing-wing required more weight than the same improvement from a new engine.

So it's not simply that it was too heavy, but too heavy compared to other moving goalposts.