Why has my 15 years plus Rose bush developed branches with very tightly clustered thorns

Question

This has happened for two years now. I prune them off, but new shoots keep re-appearing with these same clustered thorns, and they do not produce flower buds at all.

Answer 1

Oh dear. It sounds like rose rosette disease and there is no cure. It is best to remove the plant.

https://www.gardeningknowhow.com/ornamental/flowers/roses/rose-rosette-disease.htm