That's not any different than CiV. In CiV you can derp around and do whatever you want as long as you win by t300 or so. In fact the only challenge to victory, at least immortal or lower, is being run over by an early rush and being unprepared. I do think the AI is too easy on Apollo, considering it's the highest difficulty, but I don't think their win time at t250 is the issue. It's more the player can win too fast and the AI doesn't try to slow you down. But again, it's better with more sponsors, at least in the early game while they still do not respect you. With borders tight, and low respect, they DoW you more.