Parmandur
Book-Friend
2 is twice of 1, and infinitely larger than zero by percentage. 13 is twice 6.Regardless of whether 1e has 0 or 1 and 5e has two general rulebooks at this amount of time in production, both numbers = slow. Slow doesn't mean that they have to have the same number of general rules books.
1e and 5e are slow release rates. 2e, 3e and 4e were very fast release rates. There is a middle ground.
If you include Adventures, and compare material by page count, then the rate becomes higher, as 1E had a fair number of small products, but the 5E page count just in book form dwarfs the 1E page count at 6.5 years.
No matter which metric we go with, the rate is at least double. That is a middle ground.