Has radio reception improved since 1990?

Likely the tower has had some upgrades. Have you moved the radio in that time? Even a foot or so?

The radio is 25 years old, so it could not have improved. Radios don’t “age” like wine. But the transmission from the station may be much better from refinements in technology.

Does it seem to be better to you?

It might be worse if new buildings have gone up between you and the transmitter. It might be better if new relay transmitters have gone up for your area. The likelihood is you won’t notice much difference.

They can get better if the op moved it to a better spot. Components can start to drift and actually improve tuning. It’s usually for the worse though. 98% more likely the source station has improved

Impedance changes can occur with the aging of components. This means that either the antenna may be better tuned or the sound quality may improve or both.

Although it’s very unlikely, your hearing may be better if you have improved your health.

Gosh, who would know? I don’t know anyone who even listens to radio any more.