Unfortunately, it is true. I can't speak authoritatively to the speakers since they are so varied sounding and there is so much personal preference at play, but having sold both AR and Advent back in their heyday, I can say I wasn't a fan - except for double Advents - that was special!
Pioneers, Kenwoods and their ilk from the late '80's up were designed to cram as many features as possible into a box at a specific price point. Sound quality was secondary. As a matter of fact, very soon after that most manufacturers switched to the awful Sanyo STK module amps, driving audio quality straight off a cliff.
Having looked over the schematics, the VSX-D1S is categorically not a revised SX-3900. The VSX line is heavily IC based with massive use of CMOS switching, multiple DSPs and video circuitry, while the 3900 is clearly a more audio-conscientious design - right down to the discrete transistors in its phono preamp. The VSX is probably OK for what it is, but it is not the kind of quality that is normally found true vintage equipment.