So you are accepting that even if Microsoft advertises IE (it does on this forum itself), then also it won't gain market share but if Google advertises, then it gains market share.
Firstly, Microsoft can't advertise the way Google can. Google's homepage is the most visited page in the world. Their Adsense service is the most used in the world. YouTube again is the third most used website in the world. Just having something like "Try out Google Chrome" would woo so many people you'd ever imagine.
Anyways, it is not an argument but don't put Chrome behind FF & Opera. It is as powerful as them if not better.
Chrome, Firefox and Opera are my default browsers in Linux, Mac and Windows respectively.
And I tried FF 4 today. Its minimalistic UI is great (borrowed from Chrome), Single menu for options at top is great (borrowed from Opera, which borrowed it from Chrome) & even tabs management has improved - now tabs pull out flexibly as new window & can be merged into single window(again copied from Chrome). Speed is still slower than Chrome.
Even the "about" box checks for updates like Chrome.
Everyone copied the very idea of a web browser from Mosaic.
Internet Explorer 7 has to be the first browser which gave the minimalistic UI by getting rid of the menu bar by default.
No one talks about it? But Chrome got rid of the title bar, I must say.
Here's how Opera looked to me 4 years ago with a very minor tweak:
*img40.imageshack.us/img40/3525/omenubarbutton.png
And here's how it looked in Mac:
*img62.imageshack.us/img62/6051/opera9.th.jpg (Menus are always on top for a Mac application)
Notice the closed tabs button on the right corner.
You could customize your UI completely in Opera since the version 6/7.
*img705.imageshack.us/img705/6910/operacustomize.th.jpg Drag and drop items to remove them.
Things existed before Chrome came, you just had to discover them.
Everyone copies things from everywhere. Nothing wrong.