You're 100% right and its even severe than that: I daily drive on xhigh. I really try to avoid it, but when reconciling APIs across two large codebases you really start pressing north of 200k. I find myself topping out at 800k sometimes and that's with careful context management. I actually had to drop to GPT 5.4 for 1M context in my subscription because GPT 5.5 tops out at 272k. Hitting 800k context is better than repeatedly hitting let's say 200k out of 272k with multiple rounds of compaction. I run Can's snapcompact and while its better than normal compaction it still lobotomizes the model more than running with a very high context window.