If people started using bitcoin for micro payments, then I am sure the mempool will just clog and make it expensive, so you will be paying $12 fee for $7 coffee which makes it bitcoin is not suitable for micropayments but with LN it is possible to an extent but I am not sure that everyone like a mother or grandpa will go through all the hassle of creating a channel and maintain the liquidity unless they were forced to do.
Bitcoin is suitable for bigger transactions, something that is huge and makes it perfect to act on our own with no third party to decide what we should do.
You're right, Lightning Network would have been the only solution to make fees cheaper and faster for micro transactions but it still needs more improvement. First I thought about having more miners to join the network but that is even a more terrible idea. No matter the number of miners it cant increase transactions that will be included in each block.
If this ever happens, we will be having pending transactions, instant payment will be the problem. So sellers will have to wait to confirm pending transactions. There is no possibility of this happening anyway.