Your solution simply added mandated hard forks each time there is a big price rise to reduce the minimum fee.
Not necessarily. You can have a minimum fee scaling factor in a configuration file.
After all, this is not a consensus parameter. So after the price has gone up by an order of magnitude
for a long enough period, you could agree to have as many nodes as possible to update this scaling factor
to be 10 times larger. Over time, more and more nodes will adopt this new value, and allow
the mempool acceptance and relay of transactions with 10x smaller fees.