York County uses 500mhz P25 trunking while Cumerland County uses 800mhz OpenSky.
The reason for York's chosing 500mhz was lack of sufficient available 800mhz frequencies (bordering the Baltimore metro area is a huge reason for this) AND 800mhz would have required 10+ additional towers. York County is, for the most part, rural, with a handful of urban centers. 500mhz is a happy medium to answer these different terrains.
As for lowband, York County abandoned all but one of it's 33mhz frequencies. It kept one for coordination with mainly medical helicopters, and only operates from 1 transmission site in the center of the county, making is unreliable for land-based mutual aid communication.
What I don't understand from the article is that it states that there is already a working patch between York County and PA State Police. PA State Police are using OpenSky 800mhz JUST LIKE Cumberland County. So if it worked for one, why not the other?
This is just another press release from YC911's Mr. Bistline trying to blow sunshine and make people think that they are really fixing problems. In reality, they just publish the fix of one problem over and over to make it appear that they are working hard. Interoperability solutions exist that can connect tin cans to Wendys drive-through headsets. Don't pat yourself on the back for purchasing something that's existed for years but you just discovered it.