I am not sure I agree with that. Yes, the technology is there, but I think you may be underestimating what it's going to cost to produce enough of that fuel to run our economy.
First, I question whether we have enough arable land to grow enough of the stuff, particularly with all the population growth we've had. Even if we do, remember that the cost of soybeans (and every other crop) is low because of oil. If oil is no longer available, then the price of all those crops will go up a lot, both because farms burn oil and because they use the chemicals derived from oil for fertilizer and pesticides.
Then you've got to process the crop, and that takes oil. Of course, we can do all that without oil, but if we do, then the cost of the crop will go up to an even higher price than it is at now.
And it really isn't very affordable even now, compared to oil. I think we're looking at a scenario where we would be lucky to have 1/2 the standard of living that we now have.
We could go on all day, but I really have to get some work done. Please see post 82, and have a great week.