One day we will be able to do DNS CFD at will and at reasonable cost. That day is a long way off, however, at least in terms of the lives of most F1 teams. Yes, I know that computers get more powerful at an astonishing rate but here's something discussing how CFD trails that increase quite markedly at this level.
from: http://eprints.soton.ac.uk/66182/1/A_primer_on_DNS.pdfTherefore, doubling the Reynolds number
from a currently attainable value would increase the computational cost (i.e. CPU time,
memory) by roughly a factor of 11! Assuming that the current trend of doubling computing
power every 18 months continues and numerical algorithms scale perfectly for even larger
grid counts, this implies that for this flow the Reynolds number can be doubled only every
five to six years. Although the exact Reynolds-number scaling of the cost will vary from flow
to flow, and will not always be as stringent as for homogeneous isotropic turbulence,‡ the
general point still holds that we are currently far away, and will remain so for the foreseeable
future, from being able to perform DNS for Reynolds numbers typical of full-scale engineering
and especially geophysical applications.
As for cost, the current top supercomputer is in China (they're all basically state-owned at this level), cost $390million and consumes 24MW including cooling requirements (info from Wiki). We're a long way off before this level of performance (which is really needed to replace a wind tunnel fully) is available and usable by a racing car company.