Chain gate? The hell with chain gate, once you have epic spellcasting, the game basically becomes a "What's the craziest thing I can think up?". That could include gating. It could include researching an ever escalating series of insanely powerful buffs, each of which lets you research more badass spells. It could include creating your own world and populating it with monsters and adventurers, who you watch run around like rats in a maze.
The point is, all limits are long, long gone ridiculously before you'll hit level 100, making actually reaching that level mostly irrelevant.