It's the old "slippery slope" theory or "give an inch and then take a mile". Some examples:
Log Cabin syrup when I was a kid was almost pure maple syrup. Then one year they came out with a "modified" blend that had a lot of corn syrup or something. There was a kind of "apology" on the special label (I remember a blue tag or blue letters that stood out on the bottle) that explained the percentage of maple syrup was lower because of a particularly short run of maple syrup that year. Did they return to the original formula ever again, of course not!
ATM withdrawals originally were free and I thought, wow, the banks are saving so much money employing less bank tellers! Then the fees began without explanation.
When I was a kid, gasoline stations were on every corner participating in "gas wars' seeing who could sell the cheapest. Then we had a "gasoline crises" in the 1970's. Funny thing, during the gas crises I could still find gasoline, just had to shop around, that's all. Never ran out of gas before, during, or after the gas crises (so maybe there was no gas crises after all). After this period, the gas wars never returned, although the crises "ended".
Now the youtube videos are following the same pattern.
P.S. I believe any advertisement that claims an item is "free" should be banned. The only truth in those claims is the item is included in your purchase. Please correct me if I am wrong.