Who needs Excel? You're right. No one needs Excel, much less OpenOffice, or computers, or so one. Excel is a tool, one that many people and businesses ALREADY own. If a large company that is my bread and butter owns Excel, and they need something that talks to Excel, guess what, I'm going to work with Excel. I'm not going to be an effete snob, sniff, and tell them that I only support OpenOffice.
If a company, like Microsoft, wants to release a closed format that is their perogative, and their right, and I make the choice to whether or not to support it. You make the choice not to support it. That's how freedom works, that's how capitalism works. Go home, and stop telling us all what to do.