Got $$ ? PTA's and the 10% in NYC

AT NEST+m, G&T Citywide on the Lower East Side, the 'suggested' donation for each family is $1000. Many parents (myself NOT included) mistakenly think that because their child 'scored' a seat at one of the very few G&T available by the NYC/DOE, they (the families) should be happy to foot the bills for whatever the principals want. AT NEST this year, the general fund raising was expanded, when Principal Livanis decided to cut the number of cluster and other teachers, eliminating Dance, Chess and at least one teacher position in the lower grades. The PTA at NEST is a good support for the school community generally, but the idea that she (the Principal) KNOWS that parents can/will fill in to restore services is a controversial topic.
For example, at NEST, where Technology is part of the name (new explorations in science, TECHNOLOGY and math), my son has not had a single Technology focus class since KINDERGARTEN! Until this term, when the PTA got permission and then raised monies for a Technology teacher... isnt that shocking to anyone at all?
Schools which are not eligible for any federal Title I funding (due to rather affluent demographics of the student body) tend to use the PTA's in this manner. And there are certainly some legitimate arguments to be made (we - the parents, can afford it, have our kids in a high performing school, etc etc)... but isnt there a problem with the principals strategically cutting programs that they KNOW the parents/PTA's will cover?
The current way the principals are told to manage their financial pool is an issue. And, if programs cease to exist in schools simply because PTA and Parent Groups dont have the resources, what does that say about the political voices in terms of PUBLIC (tax paid, free) education for the vast majority of our students ??