Even looking at closely spaced exits now, such as Exits 10 and 11, Exit 10 was originally where Exit 11 is now, and didn't connect to the Garden State Parkway, which didn't exist at the time.
Interesting... where was the original exit 11?
So this shows the exit numbers were fairly close.
https://external-preview.redd.it/pqkFowWtBy-PH0TcviA5tJpGSMrn5Qv9asmsTwXBp5E.jpg?auto=webp&v=enabled&s=b67dbd8fafbf998325687784e44734657c5eb92eBut it's a bit confusing and doesn't truly match up with history. Someone claimed this was 1950 per the handwritten date at the top. Yet the Turnpike opened in November 1951.
It shows the Garden State Parkway was Exit 10...but there is no road at Exit 10. The original exit connected with CR 514 (at least what is now known as CR 514). The Garden State Parkway started construction in 1952 and opened in 1954. So there's a bit of confusion as to how the first few years of the Turnpike actually existed.
I'm guessing that NJTA and PTC wouldn't use their own funding to connect to free Interstates only because they wanted drivers to stay on their toll road instead of using free roads. And who suffered for that? The general public who couldn't conveniently transit from the Pennsy Pike to I-95 or from the NJT to NJ 42/A.C. Expwy.
In this theory, the distance between NJ 42 and NJ 168 is about 2 miles. At roughly 1 cent per mile back in the 1950's and 60's, the Turnpike was missing out on 2 cents per traveler going south, and gaining 2 cents per traveler going north. The AC Expressway opened in 1964.
The original routing of I-95 in NJ would've followed I-287 for a few miles before branching off. The NJ Turnpike created the interchange to allow for this movement to occur.
For the PA Turnpike travelers going towards the East would get off several miles sooner onto Rt. 1 to connect to I-95. Travelers coming from NJ would get off on US 13.
Also in this theory, why would the PA Turnpike not only make a large connection with I-76, but continue the designation of I-76 off the Turnpike towards Philly? Why wouldn't the entire PA Turnpike just remain I-76 to keep traffic on the Turnpike?
For these reasons, the theory that the Turnpikes did everything they could to keep motorists on their roads really doesn't make much sense.