I fail to see the difference. Private contracts often go over budget. The F-35 itself is full of privately contracted parts. Many public/private partnerships contracts are even no bid, meaning they are essentially uncompetitive. Whether the government hires people directly to do a job or whether they contract it out is equally distortionary. By allocating tax dollars to a public rocket lab or to a private rocket company you are increasing the demand for rocket engineers and thus creating a "rocket engineer" jobs program.