Are Non-Stick Bread Pans Destined to Fail?
If they have a Teflon coating, they may be building up a patina of partially polymerized oil. Oils that sit in contact with Teflon while being heated will gum up and form a layer on top of the coating that is a bit sticky, and prevents the Teflon from working properly. Interestingly the polymerization process is similar to what occurs on a seasoned cast-iron pan, but in its incomplete state, it is sticky rather than slippery!

All-Clad recommends scrubbing their non-stick pans periodically with baking soda to remove the polymer layer, which would be good advice for any non-stick pans.

That said, I'm not sure that it will entirely fix your problem, but it is worth trying before you replace the pans. Micro-scratches and other things will make non-stick surfaces more sticky over time as well.