A lot of FOSS development is actually done by employees of commercial operations during their work hours, with the blessing of their employer. I have been involved in a couple of companies developing network appliances based on embedded Linux. We have gained huge leverage from using FOSS software and in return we have made major contributions back to the Linux kernel and other projects. Several of my colleagues spend a significant proportion of their working hours as maintainer of FOSS projects. The company is enlightened enough to recognize that this is a benefit to them.
The quality of FOSS projects does vary widely, but some of it (usually popular and widely used applications) is very good and as well supported as any proprietary product. Some proprietary software is truly awful as well
Cheers,
Rick.