Why don't power meters measure volt-amps
Sometimes the power company will charge you. The issue isn't that the power companies need to make more "power", rather poor power factors mean that various equipment which transfers the power from the station to your house has to be bulkier, and thus more expensive.

In the past traditionally this was only a major concern for industrial customers who had very large loads and/or poor power factors. However, as our homes are filled with more and more switch mode power supplies (particularly those without active PFC) real and reactive loading becomes a larger issue for power companies. Traditionally households didn't use much electricity and had pretty high power factors to begin with so the companies don't bother.

As of late, though, it's become more of an issue with residential customers because we have more gadgets and are using more switch mode supplies which can have really low power factors. It's such a concern that in the EU they've passed regulation requiring larger SMPS's to have some sort of power factor correction to reduce the reactive loading.

Incidentally, there are some power companies with "smart meters" which charge higher peak usage rates, and offer free nights/weekends. They can do this because the actual amount of electricity you use is relatively cheap, but all of the "grid" part is quite expensive, especially if everyone wants to turn their gadgets on at the same time.