I know this is a topic that has probably been beat to death but is it just me that doesn't hear it or can't find the perfect setup?
Let me start by asking some questions. What do you expect the perfect setup to do? What does it sound like? What does it accomplish?
I've been playing for a little over 40 years, too, and have also been through a silly number of amps. When I started, I really didn't have any specific sound or style in mind, I just wanted to make the music that satisfied that craving. Didn't matter that much what I was playing on or playing through, only that I
was playing. My perfect setup was the first amp I got that wasn't a complete POS and it's still the standard I measure everything else against. Over the years, I've experimented with many different sounds and still enjoy doing that because it inspires me to play differently, much like I don't play the same on a Les Paul as I do on a Jackson Soloist. In the end, though, I still sound like me and that's all that really matters to me.
I'm not in the same league and not trying to imply a comparison, but for instance, EVH sounded like EVH on any rig and anyone else who played his rig didn't sound like him, at all, apparently. Or that it didn't matter what Page, Clapton, Hendrix, BB King, and many other examples, were playing or playing through. They all sounded like themselves, whether it was a Fender Champ, a Sears special, or a solid-state Lab Series. After that, it just becomes a matter or whether or not a specific guitar or amp or whatever works for you or it doesn't.
So, to answer your question, no, there's not much difference between a DSL and a Friedman, Bogner, or anything else that's basically a modified Marshall circuit. Whether or not they sound better is a matter of preference. There is some difference in feel, but again, that's a matter of preference. Everything in the rig affects the sound. Hands > speakers > amp > pickups > strings > cables > wood. To include every other variable. None of it really matters as long as you're inspired to play. Whatever inspires you the most is my idea of a perfect setup.