Continually setting the bar on dumb. That takes a special talent.
Schenley High sold cheap because it is on the National Registry of Historic Places, is a contributing property to the Schenley Farms National and city historic districts, and is a PHLF historic landmark. No developer would be able to get a significant alteration to the exterior of that structure through the neighborhood and city planning and historic review commissions. Therefore, the repurposement of that site is limited and forces the owner to deal with the asbestos issues. That said, the 4 acre building and site sold for $5.2 million in 2013 (and yes, I still think Pitt was absolutely stupid not to jump on it even with the political backlash that would have followed it going to a non-profit).
For sites that you could actually redevelop in central/sough Oakland, 1.5 acres that serves as the site of one of those hotel/student housing development plots along the western part of Forbes Ave recently sold for $8.2 million. An adjacent 0.3 acre site went for $400K to the same developer. So you are talking over $4 million an acre. And Oakland has the priciest per square feet office rental rates in Western PA. It is a sellers market.
How many contiguous acres of land, that can be redeveloped, do you think you need for a D1 FBS quality football stadium? The smallest NFL stadium footprint, Seattle's, fits on 30 acres. That is half of most stadiums (like the 60 acres just bought in LA for a potential stadium project). Try finding 30 contiguous acres that can legitimately be developed in Oakland (and corrdinating that many different land owners willing to sell), find $100-150 million just for the land, and then try to get the designs past all the local and city review commissions. They can't even close a one block stretch of Bigelow Blvd after 50 years of trying.
The idea is ludicrous.