They exist but most can not serve as drop in replacements for various reasons. Appropriate funding (which most lack) would enable such projects to tackle the m

They exist but most can not serve as drop in replacements for various reasons. Appropriate funding (which most lack) would enable such projects to tackle the many, often hard to solve details to get there. Moreover these things come and go, you don't want to jump the ship and then realize that there are effectively no contributors left because all of the few were hobbyists or researches who have no time anymore or moved to doing something else.