They're simply completely different breeds. Factory-farmed supermarket broiler breeds are optimized for producing as much bland, white meat as possible in as short time as possible. Everything else, like the ability to walk, is secondary, they're never getting enough space to walk anyway in their two-month life.
Breeds optimized to egg-laying are an entirely separate category, and they don't produce much meat, and the meat is… different, as you described. Apparently some hybrid breeds are also available for backyard meat+egg co-production. I don't know what their meat is like.
People didn't really eat that much chicken meat before the 70s, at least in the West. Wouldn't have been even possible to consume this much chicken meat, before these fast-growing breeds and industrial-scale farms.
Breeds optimized to egg-laying are an entirely separate category, and they don't produce much meat, and the meat is… different, as you described. Apparently some hybrid breeds are also available for backyard meat+egg co-production. I don't know what their meat is like.
People didn't really eat that much chicken meat before the 70s, at least in the West. Wouldn't have been even possible to consume this much chicken meat, before these fast-growing breeds and industrial-scale farms.