Why nobody uses McIntosh with Vandersteen?

Is it a classic mismatch or what? I mean nobody recommends Vandys for Mac and vice versa. I love both brands but if I buy Vandersteen 3A Signature I'll have to start looking for amps. I once tried hooking up 6900 to 3A Sig's and on 4Ohms the sound was dead while on 8 Ohms it was alive but thin. Is it the autoformers?
Rugged. I like that terminology. Rarely do you see that word attributed to an amp. I like it...rugged.
I had the different, but still unpleasant reaction using MA6600 with Klipsch Cornwall III's, plenty of bass, but too bright, just when things got hoping, the horns would get over-driven. I ended up just using the MA6600 front end to drive a tube backend. (Luxman MB-3045) That synergy worked much better. Someday the Cornwall's will get swapped for B&W 805's.
UPDATE: I now change my McIntosh MC2100 (105wpc) to McIntosh MC601 monoblock (600watts) and a McIntosh C2300 tube preamp. It's jaw dropping, the Vandersteen really woke up significantly.