I’m in favor of no entry fees for the park. (Overnight campground fees I support.) Over two-thirds of NPS units do not charge fees, so there is no requirement that they do so.
In our Lakeshore’s case there is no single gateway entrance where it is logical to collect a fee, an entrance such as you find in Yosemite or Yellowstone. Instead there are three separate mainland sections, surrounded by heavily developed residential, commercial and tourism infrastructure. If a person walks out of their condo at the Homestead to explore the surrounding shoreline or forest and they happen to go onto NPS property, are they required to carry a pass with them? How about a kayaker who goes ashore at the Point for a break or a boater going over to South Manitou?
There are just too many open entry points into the Lakeshore to make paying a fee work. If everybody who steps onto park property is supposed to have a pass, that is just unenforceable. If people only using certain sections of the park, such as the Heritage Trail , the Dune Climb or the Pierce Stocking Scenic Drive, are going to be checked for a pass, that is not fair.
I am familiar with Point Reyes National Seashore, north of San Francisco, which also has a very open border and is surrounded by villages, ranches and homes. They do not charge fees and are able to maintain the park and accommodate their visitors very well.
If the park is worried about losing revenue for projects, they can rely on their partners, such as Friends of Sleeping Bear Dunes, who have a well-known track record of raising money and supporting park projects.