Why do AI companions still forget everything? The architecture problem nobody talks about

Been thinking about this a lot and wanted to discuss. Every major AI chat platform right now has basically the same memory problem - conversations are stateless. You talk to an AI for months, share personal details, build what feels like a real connection, and then one day it just. doesn't know who you are. C. AI tried pinned memories. Replika has a "memory" tab that's basically a key-value. Most others don't even attempt it. The fundamental issue is that LLMs process conversations within a fixed context window. Once a conversation exceeds that window, old messages get truncated.