Trying to say it without technical gobbledegook, when the power factor is less than 1, the available power cannot be used with 100% efficiency. When using a generator with a typical 0.7 power factor converter, the generator can supply only 70% of its rated VA, or looking the other way, the converter needs a generator rated at 143% VA of what the converter draws in watts. For example, a generator rated at 1600 VA can supply 1120 watts to a 0.7 pf converter.
There are 2 different types of power factor. The motor type is different from the power converter type, and motor power factor correction techniques will not work with a power converter. Correction in a power converter requires active circuitry. It's fairly complex but like everything else is being packaged into chips and will eventually not add a whole lot of cost. With shore power the inefficiency is still there but it's doubtful an RV user would care about it. It does affect the power company, and they meter the power factor of industrial users, charging more when it's less than 1. Because of the overall impact on the grid, the newest Energy Star guidelines require power factor correction in power supplies, and in Europe it's a government mandate. I'd expect it to become widespread in RV converters someday.
