As technology advances, so do the performance and value of products.
Some people get left behind due to the lack of information of the new products and too much information of the old.
A few pioneers use the new product and go and hype about how good it is. (Note: May not necessarily be true)
More people join the bandwagon, realize (or think - there's a difference) the old product is overhyped and not good, and move on to the new product, and the hype level of new product increases.
New product becomes overhyped.
Well, this is my version for the cycle. Gartner, Inc. has another more widely-known and adopted version here:
Hype cycle - Wikipedia, the free encyclopedia