Sorry, but grammar varies to, if you think otherwise you are indeed living your biases. The implied or mis-conjugated “be” is nothing new, and as much as you may believe otherwise, its not just something that happens in PA, it may be where you were first or only exposed to it, but its definitely not distinct to PA.
No one would claim is perfect English, but it is NOT something I have not seen or heard far afield from PA.
Oh and it evidently reaches well into Ohio.
Not biased, just relating experiences. Look, I live in central MD and was raised here, I lived in New England working there, and my dad was basically a New Englander. His family in Maine of 5 brothers and a sister, visited several times. One bro moved only down to MA and his Minn wife has the upper Midwest/Canadian accent close to my other Canadian aunt who still lives in ME. Also trip to WI for their relations and my mom’s, and none of these people or the locals struck me as using bad grammar. The blood aunt lives in AZ for umpteen decades and out there with her 4 kids never noticed much special beyond aunts manner of speaking. Another bro moved to Portland OR and his kids and the people there, nothing much to notice. My brother moved to L.A. 40 years ago and again, nothing special out there beyond his wife’s Filipina accents with their kids and the Valley Girl thing. I’ve been around the south plenty with many vacations and it’s not very shocking compared to their depiction in movies.
I’d like to see your examples of bad grammar in other regions because I just can’t think of it, and I have a strong affinity for anything related to sound.