Its kind of like the current thread of "How to be Original"
If I learn to continuously burp through the sax to make sound I am quite sure I can call myself original. But do you really want to hear it just because its Original
Im not pointing at any specific brand but there are lots of players that will endorse about any piece. Some have integrity..some of them do it for the free stuff. This is why some makers will not give away pieces. I cant discuss the business of some I know but they dont either. They may give discounts but they feel that if a player values the work they will also pay for it.
I dont keep up with the modern playing world very well. Heck..most of my endorsers bought the pieces and contacted me after the fact.
I was once told by a well known maker (not Theo BTW) that to be successful just give a lot of stuff away and the players will follow their hero...even if he does not regularly use the piece. To me that is wrong.
They probably all say what Eric says, that he's been playing the same one for 30 years, and he's switching now because this one is better. I tend to believe him, having gotten to know him through his teaching approach. He worked with them on the prototype for a couple of years, I think.
I dont doubt that many have integrity. However, some endorse or play in videos and are never seen playing the piece or instrument again. I do know of one guy in the US who gets so much stuff that he has an agreement with a music store in Europe where he ships his stuff to be sold. Basically an endorsement side business.
How much different than the brand names on athletes' jackets? Of course, they're not playing insurance or whoever sponsors sports, whereas a musician who endorses should be heard playing the stuff. Certainly true for guitars, usually. But then they have like 9 of them on stage.
When I worked for the BBC a few of the guys got some nice endorsements - specifically the trumpet player with Stomvi - later a supplier to the trumpet section of the RPO. Us two sax players, on Selmer... mmmm... shall we try and get a deal with Lavazza?
Even with guitars it is a bit suspect. John Mayer had a Fender signature model, and if you look at early pictures even before his endorsement he almost always played Fender Strats. He then left Fender, for PRS and his PRS signature model is basically a Fender Strat copy with a crappy looking headstock.
I'm sure he plays them, but I've no doubt that decision was purely financial.