Is it really open-source though? As I looked at the patents, most were filed in the late '90s (don't ask me how the grant were delayed by ~5 years, I also don't know this). The main question is that the techniques discussed in the patents were prior art before 1999? Because chanting "open source" is not really helpful here unless there are code that exists then that matches the patents.
5 year delay before granting isn't terribly unusual based on my experience with the USPTO. It takes about a year for your patent to get to the examiner, then they might have comments or questions, which it takes some time to address, then it tskes some time to get back to the top of the examiner's queue. If they deny, and you appeal, it doesn't take too much to get to 5 years.
Of course, there were some games you could play to delay almost forever, read about submarine patents, and US patent rules changed in mid 2000s for patents filed after that date, the patent exclusive use period starts when the patent is filed, not when it's issued. Any patents still pending from before that will have an exclusive use period starting on issuance, if issued.
