There are several schools of thought.

When you are supplying a scarce resource of limited size, there will be no end in escalation fighting for that space. Small blocksize, high fees, further escalating. That's drawing away customers they will discover cheaper to use money transfer possibilities.

If you are supplying unlimited resource you will just run into the tragedy of the commons. So there has to be a fixed rate at least to avoid getting spammed straight into the ground.

There seemingly isn't any possible way to offer cheap or even for free resource. People of the sorts like PayPal or Western Union will sniff out their chances of undercutting Bitcoin with ease.