Plastic outgasses as it ages making things sticky.

When I had my shop, some customers cars would sit unused for a few months as they decided if an engine replacement was worth it, engine found and shop time scheduled. With the car being unused, steering wheels and other plastics would sometimes get sticky. This outgassing is constantly occurring but as the car is used the stickiness wears off.

I just moved a mid 90's Ford that I had stored in a shaded semi trailer for 3 + years. The steering wheel felt like contact cement and looked wet with oil but it was dry when I put in storage.

How long was the car at the dealer? The only chemical I'd think that would attack plastic like you are describing is brake cleaner.