And it's not like those pushing for Brexit had a good record (I'm being kind here) of delivering on their past promises either; yet they got their way. They remain in power, have made stacks of cash and don't look to be stopping any more of that any time soon.
It's all well and good saying if whoever is in charge cock things up they'll get voted out... but that's completely ignoring the reality of who those people are, who they're controlled by and their control of the media with the ability to destroy any and all opposition. But enough folk jumped on the relevant hook that fitted with what they wanted and got them over the line.