I know it's easy to look back on the results and say it was so amazingly obvious, but look at it from a lens where you don't know the results of 2016. In this lens, the last successful republican campaign was Bush 2004. Bush 2004 won Virginia by keeping Fairfax tight and winning in Loudoun and Prince William. Bush 2004 went hard at Pennsylvania and won Chester County by 5, only lost Bucks by 2, only lost Montgomery by 10, held Kerry under 60% in Scranton, etc., but still lost by 3%. Since then, McCain spent so much time in PA that the governor was joking about charging him state income tax, and still lost by 11, and Romney managed to do great in the Pittsburgh Suburbs, but ended up bleeding votes in Philly vs. '04 in return, and lost by a Bush 2000 margin. Simply put, from a pre-2016 viewpoint, the last winnable PA formula was in 1988 during a 400 electoral vote landslide (probably not realistic in the modern era for either political party), while the last winnable VA formula was far more recent - 2004. Furthermore, Trump's formula for winning PA was not predictable in advance for anyone who wanted to stay politically relevant - if you went around saying that Clinton was only going to win Scranton by 3% after Obama won it by 27%, you'd be laughed out of politics in 5 seconds.
Not really. NC Yankee already explained most of it, plus it is worth mentioning that there were many polls showing Republicans (especially Toomey in his Senate race) doing better in PA than VA, and that was long before Trump became the nominee. A possible "winning formula" for PA was pretty obvious back then, it would have been something like PA-SEN 2010 (with the GOP nominee outperforming Toomey in the rural areas but doing worse in the Philly suburbs). The long-term trends in VA favor the Democrats, people should have realized this.
To be fair, at some point in 2015 I also considered VA a Tossup (sad!), but I always expected PA to vote to the right of VA in 2016 and repeatedly made it clear that triaging PA/WI in favor of VA would be a recipe for disaster.
Any Republican strategist who relies on this logical fallacy should be fired. Arizona has voted Republican in 12 of the last 13 elections, does that mean that Democrats shouldn't contest the state in 2020?
Cry while Trump is president.
I can't wait until the next time Republicans lose the gubernatorial race when a Democrat is president.