It died when the CPUs went very high in TDP. Peltiers capable of shifting 40W in that size of area were doable but once you got to 125W CPUs peltiers couldn't do the job. I heard recently that you can get one capable of cooling a modern CPU, but I don't know how practical it would be or how much power it would consume. They are far from efficient ways to cool a CPU, your water loop needs to cope with double the heat that the CPU is putting out due to the peltier effect.
So with a 220W overclocked CPU you would need to be cooling 440W with a waterloop, and that is a lot of heat from such a small space to be cooling.