They were allowed to get away with it as with pollsters, they are only really judged on their "final" poll. So Rasmussen (and others) could have this a horse race right until the end and then show Trump +5 on the last day - so long as their final poll is somewhat close, they will be considered accurate and reliable for future election cycles.
Nobody remembers that the pollsters had Carter with a double digit lead over Reagan through most of October 1980!
Also, weren’t the media quite positive that Reagan would start a world war? The end of the world, etc.
Yes, I believe you are correct about the so-called Reagan surge and the polls. Only a “final” poll can be graded for accuracy. Any other poll before that, the pollsters are free to do what they want.