The interview was quite interesting. It also makes sense that Shenmue was not a ps2 title. I am not sure if is true but I believe I have read once that Shenmue was designed to use the hardware of the DC to the fulliest while the P2 hardware is really different from the ps2.
If you look at Yakuza 1 and 2 this makes senses. Compared to Yakuza 1 and 2 Shenmue 1 and especially 2 where the bette games from a technical point of view.
His words are part corporate speech at a very delicate moment at Sega but true also. There was no way he answered "its possible and while PS2 Shenmue will look different, it looks awesome." He was more open with Xbox because: probably the port was already on the works, Microsoft were partners with DC, and indeed Xbox1 was a great
console hardware.
Dreamcast had 16MB RAM to pool and 8MB Video-RAM with lots of features. After the disasterous relationship with devs and Saturn, Sega went for the ps1-type of straightforward architecture. So basically a so-so CPU (SH4) with an easier instruction set (ARM) feeded a beast of a GPU (Holly) and done.
You can say that DC strenght was video chip and weakness/bottleneck the main processor.
Check past magazines if you like, DC marketing wasn't based on Holly at all but in the console as a whole and specially the launch game line and online feature.
In other hand, Sony won the previous console war and was winning the next before even starting. They were like running with their pants down, merry times. They really wanted to give the most powerful thing to developers. So they made a supercomputer with a parallel architecture, like Saturn.
The CPU numbers double those of DC and adding paralellism computation power and DRAM (Direct access). That was Sony bet. Confidents enough of that calculation monster, the VRAM was half the DC. It was possible to add much more from the main but, not easily and at the price of losing CPU power.
But above all, it couldn't manage compressed textures (key in Shenmue). In a custom format, swizzled and contained in bigfile, yes; but uncompressed.
Those who remember PS2 launch, it revolved around the Emotion Engine practically in exclusive. That was, even the name, marketing stunt for "tremendous computation power".
Because saying to the press "it calculates so fast" is lame, so "emotion".
To cut it already, ironically Sony and Sega inverted roles at hardware design but with different results.
And Shenmue on PS2 would've looked somehow bland textured but really well shaded (similar to MGS2) or keeping the texture amount but with less resolution.