Valved Trombones, their faded glory

I think the reasons we no longer see them is that they outlived their usefulness They came in many sizes and with different valve systems and at one time were very popular. I have my own theory on this subject and I actually played an Eb tenor valved trombone in the 1970s for a period of about 5 years. I acquired it in Kiel Wisconsin at an antique store. It was a refugee from an estate sale that did’nt sell and was consigned to languish away in an obscure corner of the shop. Mine came with its original coffin case, a lyre and original mouthpiece. There was also a crook to put it in the key of C. All things considered, it played rather well and research indicated that it belonged to a William Voss of Kiel Wisconsin. It has string action rotary valves that appear to have been made in New York or the New England states shortly after the Civil War.

Now, to my theory of why valved trombones are no longer used. I think they were used in lieu of slide trombones when the regimental bands were in vogue. They were much more durable than slide trombones and took the rough handling of a field band. Add to that the number of regimental bands that were mounted on horseback and required the musician to hold reins in one hand and play with the other, and you have the answer! European Bands still have bands mounted on horseback, and I would wager that some of them, especially British bands may occasionally still use a valved trombone rather than a Bb tenor horn.

Is there anybody out there that has another view of the valved trombones exit from todays brass bands?