Minwax polyurethane not drying. Cross linking is what makes polyurethane finishes more durable than other finishes. It takes a little longer but it should not take weeks if the finish was good and properly mixed. Apply a thin coat of minwax fast drying polyurethane using a high quality natural or foam brush. For floor projects use a square buff orbital or disk type sander with 220 grit sandpaper or the equivalent grit pad or screen specifically designed for sanding between coats.
After the first coat i used 220 grit sandpaper to lightly sand the surface as recommended. Its more likely that the wood youre finishing contains a natural oil or you have applied an oil to the wood and the oil hasnt dried. Do not use a belt or drum type sander for sanding between coats. If you experience oil based polyurethane not drying well its not likely that its bad polyurethane.
My guess is that either the can of finish was bad or that it was very humid when you applied it. I used 2 coats. The second stage of drying is cross linking where the molecules react in the presence of oxygen to bond with one another. I used minwax quick drying polyurethane to topcoat a dining room table.
You did not say where you live but in some states such as california minwax uses a different formula for thier poly in order to comply with environmental regulations. Miniwax polyshades is little more than tinted polyurethane so your drying problem has to do with the varnish type finish not drying rather than the stain.