Hillsboro to PDX is on a public transit system that is heavily subsidized by taxes. A privately operated railroad (even if the underlying infrastructure is publicly built and owned) has to make money. So $30 for a 23 mile ride is not out of the question. That's especially true if the drive is inconvenient (or, for taxi/Uber/Lyft, as expensive or more so than the train).

Sometimes even public railroads can be expensive. See many Amtrak services. Also, airports usually charge an access fee even for public transit - so BART costs considerably more if you get on or off at SFO than it does if you go a bit farther to Millbrae. Caltrain, which has to mostly cover operating costs from fares, has notably higher fares than BART, which does not. One way or another, you have to pay for the service, and the lower the subsidy the more it comes out of your pocket when you ride.