That bridge is a service bridge, but it isn't implausible that it could be adapted for use by pedestrians to visit Ellis Island. It might involve a few $m and an environmental review, but it has been considered before.
However, despite periodic questioning and advocacy for it to be allowed for pedestrians (to decrease the cost of people visiting, and make the island more accessible), the NPS has stated that "an approach by boat is important to the experience". A $19.25 ticket, run by a private ferry company.
Go figure.
E.g. parts of the border between Switzerland and Italy is described by peaks and valleys of the alps. Now due to climate change, glaciers are melting, and suddenly parts of Switzerland and Italy are swapping. [https://www.nzz.ch/panorama/neue-landesgrenze-schweiz-und-it..., German only]
I built a, for the time, very good data logging setup for my Jeep and mapped some trails[0] in 2001. Why? The maps provided by the USFS and the timber leaseholders were (and still are) wrong.
I also made a point the first time I was in Europe of renting a car and driving to Baarle-Hertog[1] and walking to all of the enclaves, as well as enclaves within enclaves.
[0]: https://github.com/ryjones/Area29SnowmobileTrailMap
[1]: https://en.wikipedia.org/wiki/Baarle-Hertog#List_of_enclaves
There are some very sad stories related to people assuming that a road on a map is actually a road in the way people living around cities generally think of the term.
Each district is responsible for their maps which is why quality varies. They really need to standardize and enforce those standards properly.
https://en.wikipedia.org/wiki/Dahala_Khagrabari
Edit: Too late. Ceded to Bangladesh in 2015.
