It's because people tend to prefer bland and safe over lively and dangerous. The PS5 is a departure from what's normal for console design aesthetics. The XBSX kinda is, but not really, because it's just a taller, blander, more grown up version of a Gamecube. The XBSX seems more normal. The PS5 seems foreign.
The color scheme also comes into play. Black is the safest choice period. White or grey is ok but not as universal. Two tone isn't the norm. Past consoles have had things like the XB jewel at the center or chrome trim, but were otherwise one color. The only other somewhat recent console I can think of that was two tone is the XB1S, but the slim black bottom works because it's hidden underneath. Much like how the grey sides of the 360 were basically hidden. The XB1 and PS4 even had gloss and matte black, and while some liked it, some didn't. Just like the XBSS. Some like it, some don't, and it's partially because of the obvious two tone. PS5's two tone is blatant and in your face. Some people really aren't going to like that. I myself will wait for a non white version, or will paint the white portions if I have to. While I think the two tone pops and is cool looking in general, especially as a presentation piece, I don't want it in my entertainment center.
I think the younger you are, the more likely you're going to much prefer the PS5 design because of the wow factor. Kids don't really care about home decor. My 18 year old self and younger, would have thought the PS5 was amazing and XBSX was pretty meh.
Are you saying I'm old?? Jokes aside I see your point, my favorite console design is the black Wii and the Wii U a very close second because of the minimalistic design.
I know... my English sucks.