It won't be a very long time.  It's just new technology now and those who got on board early and risked with the right producers will profit most, as they should.

As the technology is easier to produce, more will do so and that supply will drive down the price of the technology in line with profitability similar to what GPUs have seen over the past few years.

The specificity of the hardware is a legitimate concern, as is how difficult it is to currently get an ASIC, but both will work themselves out through market forces.

Through all of it, and even right now, current miners have a vested interest in saying: