Sure that would be a major jump but it would only take you so far. I think what might happen is that power rates where there is excessive mining will increase. The network growth will switch to a sustainable level because of economics or regulation or maybe even wars.
How ? Why ?
- Economics : ASICs producer have (at least) a constant production rate. And probably growing. Most of their costs are
"NRE" (the first chip may cost something like one million dollar, but the next millions ones cost only pennies each). So they will not stop producing them until people stop buying them. Plus they can lower their price with time down to their marginal cost of production. In the end they will cost almost nothing and people will use them to heat their apartments.
- Regulation : please explain what kind of regulation could limit the network hashrate
- Wars : ...
The network is growing an exponential rate largely due to huge advances by moving to ASICs. Producing more of the same ASICs will allow for more of a linear growth rate which could be sustained for a long period of time. You don't get the same exponential jump in ability without a new technology. That could happen, but it is unlikely to happen in the near future.
The current ASIC companies are living high on the hog even demanding and getting pre-payment. Most of those companies won't even have the ability to cost reduce down to the marginal cost of production. Additionally why would they? What manufacture sells goods without a reasonable profit? So that would probably be another short term limiting factor. Plus if everyone started using these miners it would have a massive impact on power consumption and probably result in higher power costs, which people wouldn't like.
The amazing thing to me is the extreme growth rate isn't good for anyone but the suppliers right now. Yet so many don't seem to accept that it can't continue with such an extreme growth rate. It is common for extreme growth to flatten out to sustainable levels. The same will happen the bitcoin network. When it does it will be a good thing for everyone except the suppliers. But at least they got the rapid money up front.
The "sustainable" level of the Bitcoin network is when the cost of electricity burnt is equal to the price of the newly mined bitcoins. It has happened in the CPU/GPU era. It will happen in the ASIC era.
That is only true from the standpoint of a current miner. What will happen if the network keeps growing at the insane rate it is, there will be increased power costs and/or regulation to stop it. It isn't reasonable to think that is would be allowed to grow to 10% or more of the world's electrical power. Do you think people will be willing to live with vastly higher power bills and rolling blacks outs to support bitcoin mining? In the CPU/GPU era you weren't using nearly as much power as in being used today.
What is more likely is that the cost of entry will get so high that it will block most from mining at least bitcoin. If the cost of power is truly what limits bitcoin, then bitcoin actually won't have much of a future. Most businesses run with as high as profit margins as they can. The micro-economics don't work the same on the marco scale and the bitcoin network is way past the micro side.