They are on the commercial band so I would think they are able to convert to a commercial station. Could they maintain the programming they have? My understanding (and you may know more in this area for sure) is that they 'buy' the programming from NPR (to help fund it). Whether NPR would continue to allow a commercial station to do that if they ran more traditional ads would certainly be a change from the way it is being done now.This is all highly speculative. KUOW isn't going commercial and can't simply expand their spot breaks the way KIRO-FM can. The clocks for their anchor programs in drive time are tight and don't allow for adding many extra units.
This bizarre notion that somehow they can just convert to a commercial station and maintain the product that they have, simply with advertising, isn't how non-commercial broadcasting works. To the extent KUOW gets assistance from the CPB, they have to justify it through their performance and documentation. They earn it. This was the system set up by a conservative president to fulfill the mission of public broadcasting and not simply hand them "subsidies."
Here's what I do know as a long time media buyer: KUOW (and other NPR stations) do not get the share of ad dollars their audience ratings justify - simply because they are so 'restrictive' on what advertisers (sponsors) can say. Loosening the requirements to make it more 'advertiser friendly' even a little, would result in more ad (sponsorship) $$ coming their way. This would go a long way towards any funding deficit they incur due to the clawing back of funds. I know it's not the political story they want to tell, but in the end, they'd be healthier, self sufficient and not at the whim of politicians. The money is there to support it, the rules just need to change to level the playing field.