Interesting video. Pretty sure I've seen at least part of it before.
Quantity of money per unit of output and price index is deeply intricate. At the end of the day, the more cryptocurrency is produced without needed and real usage in economy the lower the value of your crypto assets.
I personally don't think that the creation of other crypto assets or projects necessarily will depreciate the value of bitcoins. It may decrease the market share of bitcoins in the overall crypto market, but since the crypto assets that are on sale with an initial public offering right now are completely different from bitcoin in nature (a lot probably can't even be classified as 'currency').
What will affect bitcoin's value and inflation is the rate at which it's being produced at, which right now is 12.5. The growth of bitcoin's supply is controlled, which is extremely different from the system that fiat operates in which can often leading to debasement of currency in a very short amount of time due to government mismanagement.
What you say regarding bitcoin produced without an increase in demand in the economy for BTC leading to inflation is true, but right now, I think the rate of adoption far exceeds what bitcoin's inflation figures are. And the beauty of a disinflationary system like bitcoin is that as adoption stops growing as fast as BTC gets widely adopted, so does the rate of growth in the money supply.