PLA is a plastic made of corn (it is polymerized lactic acid). It's actually a pretty versatile thermoplastic as it's semi-crystalline and so although it can be

PLA is a plastic made of corn (it is polymerized lactic acid). It's actually a pretty versatile thermoplastic as it's semi-crystalline and so although it can be formed at relatively low temperatures, if you heat treat it (which increases its crystallinity), it can withstand ~boiling temperatures like other common thermoplastics. It's also technically biodegradable, but usually won't actually break down unless thin and in proper industrial compost processes. (Which can be kind of good for many applications... you don't want your plastic breaking down while in use, although you definitely don't want to be littering PLA.) It's pretty cheap, commonly used in one-time plastic items, and is the most common 3D printing plastic. But also, you can make polypropylene and polyethylene pretty easily from methane (which can be from biological sources or synthesized from electrolyzed hydrogen and CO2) via methanol-to-olefins processes, common in China. But you're missing the point. We can synthesize literally anything you can make from oil using hydrogen, direct air captured CO2, and the Fischer-Tropsch process. It's a complete replacement for crude oil. It's just more expensive than getting it from the ground.