That's an interesting topic, and you're definitely not alone in wondering about the potential of PS2, Dreamcast, and GameCube emulation on the PS Vita. While PSP and older console emulation is quite stable and well-supported, the jump to more demanding systems like PS2 or GameCube runs into some real hardware limitations. The Vita's CPU and GPU just aren't quite up to the task for full-speed emulation of those consoles, at least not natively.
There are still creative workarounds, like remote play or cloud streaming, but native support is extremely limited. Still, it's impressive to see the ongoing passion in the community for pushing the boundaries.
If you're into mobile gaming alternatives in the meantime, trying out something like Dr Driving Game can offer a fun and smooth experience without needing to worry about hardware limitations.