Why was this thread locked?

This was one of my older threads. It was about NYC taxi medallions. I was going to bump it for discussion on recent events, but it is locked.

I do not know why. There was no moderator comment. No arguments in the thread.

The thread had no posts for a long time and was becoming a spam magnet.

You can always start a new thread and link back to the original.

Probably got bumped by a spammer.

Thanks.

If you find a thread that was locked without comment, the most likely explanation is that it was zombified by a spammer. As ecg says, some threads become spam magnets and are bumped repeatedly. Closing them gives spammers one less target.