Ah, but the SSC was built in an alternate timeline. It spawned Universal destruction. Luckily however, time travel became possible at just the right time. They sent time travelers back in time to sabotage the SSC before it could power up.

Well, that's what one novel claimed

More seriously, I also wish it had been completed. It could have kept the U.S.A at the front lines of particle research. It was a massive undertaking though and I'm not sure they were ready for it. Design issues and cost overruns were plaguing the project. Still, it seemed silly to just up and abandon it after so much work was done.