I see them everywhere still, but I don't think that's a testament to their longevity, it only means Ford sold a ****-ton of them.
Coincidentally, we recently bought a minty `89 SHO with only 16k miles on the clock. It's not just clean, it's spotless, and all original (including tires, which was a little scary). It took about $2k to make it roadworthy, because all the fluids have turned into sludge and it needed new rubber, but it may be the nicest 1st gen SHO in existence. It makes a surprisingly European sound, a neat trick since it's a Yamaha-sourced engine in an American car, and handles like a same-year 5 series (but originally cost slightly more than half as much). So while I did pay almost the same price as when it was new ($17k), I feel I got my money's worth.
Also I just got back from Sweden where they took my measurements for the Regera, I also went on a private tour (led by Christian) of the Koenigsegg factory and got to drive a Regera and a One:1 on their test track. Although they're visually similar in some ways, many of the same Koenigsegg design cues, they're very different cars to drive. While the latter is more track focused and more edgy in its handling, the Regera is buttery smooth, Veyron smooth, but unlike the Bugatti it can corner on a dime and give you back some change. The acceleration is ballistic, like a heavily steroided Tesla P85D on crack. 0-100kph times were <3 sec, about 2.5, but the real story is 100-370kph, which happens in substantially less time than most supercars can finish the 1/4 mi, without splashing your drink. Seriously, the only notion you have that you're accelerating that rapidly are the g-forces mashing you into the seat (and everything around you going by in a blur). I can't compare the sensation to anything else because I've driven nothing else like it, journalists and professional reviewers are going to lose their minds.