I think operationally this is getting more true, but not as much funding-wise, so intelligent control over appropriations is still important. For example, SpaceX is a private company, but largely publicly financed: government contracts provide the majority of their revenue, since they don't yet have significant private-sector clients. If their NASA contract were cancelled (e.g. because a committee cut that program), they wouldn't be solvent as a company.

Also common in the private-sector research world, outside a few big places like MSR that are mainly privately funded. A lot of biotech companies depend on public/private NIH research grants, and the SBIR/STTR programs are also a big source of funds for riskier research in small companies (http://www.sbir.gov/).