Kids can socialize outside of day care just fine. Confining the concept of "socialization" to institutions is a giant part of what's wrong with people today. Sure I let my kids watch some tv, but I spent a significant amount of time doing stuff with them, which I can tell has had a massive positive impact. My daughter is still traumatized by stuff other kids did to her in day care. The "socialization" that happens in day care and school is mostly indoctrination. "Do what I say or else I'll let the unmanageable kids beat the
out of you while I sit back and do nothing." If you think that's a healthy environment, you are wrong