I don't think someone would need to open 5 channels if they only had 30 transactions per month, or even if they made 150 transactions per month. There are enough well connected nodes so 2-3 open channels will be enough IMO. There are several businesses whose primary service is to open many channels with many people, and collect various fees for doing so.

I also don't see any reason why a user would be closing all their channels after only a month. I believe a more realistic use case would be a person is paid by his employer on the 1st of the month, the person pays their various bills and expenses over the next month, and repeats on the 1st of the following month. I can see a person closing a channel after say 6 months if they accumulate so much money, they no longer have enough inbound capacity to receive their paycheck, but even in this case, the person could elect to receive their salary on-chain, and not close their channels.