By "we", you mean who?
This community here that has posted the graph on Bitcoin adoption vs others a million times on this forum!
Can you explain the $20.00 tx reference and how it connects to widespread penetration of smartphones, TV, and other electronic goods?
Miners protect the network because they get the block reward, when there will be no block reward they will rely on fees, right now, we had an instance where the fees from the transactions were the same as the block reward, in that block the median fee was around 20$.
So to get the same level of protection for the network in the future as we have now, that will have to be at least the average, 24/7, forever!
OK, I misunderstood your other post. In reply to that, I can't disagree with your viewpoint. But the design decisions made by Satoshi is what we have. Were there some things that he should have made different? Perhaps, like having a tail emission or something to continue incentivizing the miners in times of low block space demand. But that's a debate for another topic.