All the people who were doing that are now pushing RCV or other election reforms that would make it realistic for third parties to be able to get all the way to winning. The third-party people who are running in FPTP elections are, almost universally, either attention-seekers or deliberate spoiler candidates. Bernie Sanders, when he was running, joined up with the Democrats instead of running as a spoiler candidate, because he's making an earnest attempt at making things better.

It doesn't really matter now because we've slipped one rung down the civilizational Maslow pyramid now, and are in for a fight to preserve the right in any capacity to elect who we want in power. But, whenever we make it back out to the other side of that, it'd be nice to remember to reconfigure the system so third parties can actually win, first, and then run third party candidates after that, not the other way around.