Somewhere in Art Pepper's autobiography he mentions something that excited him musically in his later years like when he was young. (Can't recall what it was - someone will probably remind us.) So decline in the excitement factor is a pretty general phenomenon.
Perhaps raw excitement is replaced for the continuing listenener in later years by the mature savouring of the connoisseur. Just speaking of myself, of course!
But something akin to the excitement of youth can still happen. Surprisingly, I was blown away by a local big band and a strict harmony vocal quartet a few months ago. The standard of musicianship was very high and sitting on the front row and hearing the sound coming from 22 different sources was something else!