He must have missed that one minor exception in the history of money.
This I agree with. Major changes never happen overnight. I always thought (and got laughed about it year ago) Bitcoin was looking at a 10 to 20 year road to mainstream adoption.
The "money chain" doesn't magically go from 100% fiat to 100% alternative. Companies that have Bitcoins will spend those instead of converting them if they can. If for no other reason than it saves them the cost of conversion. Our company has revenue in Bitcoins and we now pay namecheap for domain names and SSL certs in Bitcoins. Now namecheap might convert 100% of that to dollars but it still adds one link to the chain. Maybe some namecheap pays some of their costs in Bitcoins or some of their employees wish to take some of their salary in bitcoins. The chain extends one link at a time.