Simply put, by slowly getting rid of Elmo's world in a matter of at least 2 years they could end the segment completely in the main show without confusing the little kids.
You just show it less and less. Basically, one season you put it on evey other episode. the next year you put it on every third or fourth episode, and it will end without confusion.
And if Elmo's World is a seperate show, they can use that to measure the segment's success. if it's a failure, Elmo's world would be gone. If it's a success, they keep Elmo's World its own sepperate show. Get it?
You just show it less and less. Basically, one season you put it on evey other episode. the next year you put it on every third or fourth episode, and it will end without confusion.
And if Elmo's World is a seperate show, they can use that to measure the segment's success. if it's a failure, Elmo's world would be gone. If it's a success, they keep Elmo's World its own sepperate show. Get it?