It's basic marketing. Draw in the followers under false pretense, then all you have to do is worry about maintaining them which is much easier than bringing them in under honest terms.

This can be seen in politics as well. How often do electees follow what they were promising constituents while in the running. Then they'll do the same thing again and make a big fuss for the week or 2 prior to reelection, then go back to business as normal.

Likewise with products. Get the customer to come into the store, visit your website, or call a number. Then by the time they see it, or in some cases have already made a purchase, and find out thing aren't as advertised it's either already too late with s purchase made or they've "come too far" and the shortfalls are close enough to where they shrug and purchase anyways.