It is a natural alternative. The "simpler but more cores" project works on paper (i.e. potential instruction throughput). In reality it falls apart for variety of reasons. The most fundamental is because of the difficulty of exploiting thread-level parallelism. The complex Out-of-Order cores do a really good job of improving throughput by finding independent instructions to execute in parallel. The path-to-parallelism is much easier at the granularity of instructions than at the granularity of cores. Parallel programming is hard. Amadahls law cannot be avoided except through ----- speculation, so we are back to complexity again.