Right now the barrier to entry is relatively low. Miners just need cheap electricity and off the shelf GPUs to get started. It's also well known to use and get started with building your own mining cluster.
The only way to fix it is to introduce graduated electricity rates that increase as more electricity is used.
Have you looked into mining Bitcoin with GPUs lately? You would need free GPUs and free electricity to justify the effort to set it up...
BTC is only profitable with a. ASICs b. Very cheap energy source
Same is increasingly true for other coins.