True, and I suppose the patent is expired by now so you could in theory start making it. Though the FDA has rules about how you can produce such things. Probably better for a company to risk/start a new vaccine which they can patent and thus get some benefit that way vs one out of patent. Also just because you can legally make it doesn't mean it is practical. It may require other things that are not longer made, or specific equipment that would be expensive to recreate. Still this is an opportunity for someone in India (where a lot of generic drugs are made already, though the country doesn't matter) if they want to.

I don't hike as much in areas where Lyme is common as I used to, but I'd still take a vaccine if I could. (I didn't know the vaccine existed in 2001 or I would have)