There are companies like Novartis that are making glyphosate using the original now expired patent.
Monsanto has updated the product with a slightly improved formulation. I'm enough removed nowadays to be able to tell you if it's worth the slight extra money, but Monsanto still has the majority of the market.
I couldn't find reliable market share figures, but I think Monsanto has nowhere near a majority of glyphosate market. The patent expired 25 years ago and glyphosate has since been made by many American, European and e.g. Chinese manufactures (BASF, Dow, Bayer, Syngenta, SinoChem, ChemChina, and whatever). I'm actually surprised if Monsanto's global glyphosate market share is a two digits percentage.
I thought that "Roundup ready" described the GMO crops and that the weedkiller was just "Roundup."