That's a bit too reductive, when you realize that halving block rewards will likely make these high-value transactions at some future point, and you're not including the value of time
Why would it be a high value transaction? Only possible with a fee market. No one will use Memo with high fees.
Lol the existence of "fee markets" is a joke, fees disincentivize use. Transactions can be high value if they attract more use or attention to the blockchain
Not at current levels, right now the block reward is the majority of the incentive for mining. Average miners don't see any of those fees after pool and network fees are deducted
Source: mining for 3 years. Excess network activity doesn't mean anything if there isn't actual adoption bringing price up with it, nobody mines BTC just for those