CSS - Moving to CSS based layout

I am in the midst of reading ‘More Eric Meyer on CSS’ . The first chapter talks about the move to CSS based visual design. For example --

“…for years upon years – about eight of them as this is being written – we’ve been using tables and spacer images to lay out web pages. For the first part of all those years, it was the only way to create compelling visual design…when CSS came along, there began to be some hope that this trend might reverse…when CSS2 introduced positioning, the door was opened.”

I poked around some big name sites to see whether they use table or CSS based layout. Here’s what I found:

Examples of big name sites that use

I wonder what’s holding Microsoft, Yahoo and Google from converting to a full CSS based visual layout. Please correct me if I am wrong in my assumptions about Google and Yahoo using mainly Table based layout.