I graduated from Lehigh U. 40+ years ago. Really enjoyed the area, sorry to here its developing so much.
Development is a sad, yet natural thing. It makes some folks rich by increasing property values for a time. But if you hold on too long and things don't work out right, it will inevitably decrease that value.
My wife's family, except for her brother, made their tearful exit in 2003. My father-in-law was trying to finish out his career, and took a job in Louisiana, and finally Wilmington, NC. The house he built in the early 80s for $50k sold for around $300k. There are many factors as to why, but overall, it was a good thing.
My first visit to the Lehigh Valley was in 2006, and though much more congested now than then, I can say that I was astounded at the improvement that seemed to be taking place. A few new factories have really been a breath of fresh air for the area. New parks and shopping centers are popping up everywhere. Despite the sad loss of undeveloped land, it looks like a welcoming place, barring the inner city parts.
The negative aspect is the fact that it seems to be converting slowly into a suburb of New Jersey and New York City, which has had a strange impact. Jaguars, Mercedes Benz, BMWs, and Escalades are slowly replacing the old farm trucks and frugal family cars that used to roam the area. Downtown Allentown and Bethlehem, which were once safe areas, are now (from all my sources) becoming dangerous areas. Also, many old farmers and selling their small 100 acres farms, and the buyers are cutting it up into .5 acre lots, and turning the landscape into something resembling an Edward Scissorhands type neighborhood.
Despite all these changes, I will say that the area as a whole still has many times the quantity, and quality of old farms, houses, buildings, and tiny "wagon roads" that I grew up around in the Deep South.
I've often wondered why the Deep South does not have as many old houses and buildings as Virginia, Maryland, and Pennsylvania does. I think I can attribute that to A) a strong push by locals to preserve and maintain older properties; B) the climate in the South, such as humidity, tornadoes, hurricanes, etc., has been cruel to the old buildings; C) the Yankees burned us out. I'm sure I'm wrong about part of that.. maybe...