There's nothing inherently wrong with PPC or superior with X86, it simply was a case of demand driving down the price. Before the switch Apple was perhaps 4 % of the market, not enough to make a difference to IBM. When Apple wanted a more powerful PPC for laptops IBM told them to just wait and we'll get around to it, eventually, some day, real soon now. So Apple gave in. Even the desktop chips, the "military spec" G5s were falling desperately behind X86. The choice was clear, expensive, slow, rare PPC or cheap, fast, common X86. The choice was obvious.