So, what changed?
No more Ordinals NFTs and BRC20 spamming the mempool is the reason. They made the mempool become very congested than it should be and not people have dumped them.
Will these low fees continue in the long term, or might we see another spike in fees when the price of Bitcoin surges again?
When you are talking about was not the first time bitcoin mempool was congested, but the it was congested. It will not be the last time but know that it will later become less congested again.