>Nobody is using lead-acid anymore, which shows how out of touch these idiots are with reality. For 5, if not 10 years LiFePO4 batteries have been the best option even for DIY systems

Ok, but they often are lead acid batteries. I just bought an inverter off a guy with lead acid batteries. They exist like crazy all over the place because lead acid can be reconditioned effectively forever with proper equalization. If you have lots of solar and you value repairability with simple tools and simple skills lead acid still has a niche