If each and every single transaction is levied fees, then people wont spend as much as they spend with cash.
Depends on what you're buying. If you've fulled the supermarket trolley, then an extra $0.10 - $0.50 isn't going to harm much. I agree that for micro-transactions, cash is instant and transactions are settled without fees. This is why we have Lightning.
The so called lightning network defense is not prudent as in lightning network the sellers ids is being broadcasted to everyone.
What's "sellers ids"?
In my option the fact that you have to wait 30-40 min for verification is even more important than the fees.
But, you don't have to. If you opt-out RBF, it's realistically impossible to double-spend. Only if you bribe a miner, you
increase your chances of having it replaced by another transaction. For weekly transactions, wherein you pay $100 - $500 to the supermarket, it's fine to accept unconfirmed transactions.
Even with 1 sat/vbyte, it's very improbably to not be confirmed within 2 weeks, which is the default time required to dump it from the mempool.