Nationally, a typical museum gets only 4% of its earned revenue from admissions. With the help of its own multi-year grant, the Dallas Museum of Art eliminated its $10 general admission — while still charging for special exhibitions — and saw annual attendance jump to 668,000 from 498,000. It is a commonly known fact that people prefer free things.
Museums cost money to operate and run just like any other home or business. This is why there must be a charge or fee for visitors to enter and see the museum. The museums cannot rely on public funding to be enough money to pay all of the bills and operating costs.
No, all museums should not be free to enter, because a museum needs to raise funds to meet its operating costs. A museum is a business, even if it is non-profit. It still must meet its operating expenses and pay its bills. Although it would be nice if all museums could be free, this is simply not feasible for most museums.