The first is that the tax bills were essentially a charade. Despite the concerns of some local tech-company folks, Philadelphia's tax policy regarding stock options was never anything they needed to worry about. Nevertheless, it made for a nice bit of publicity, a chance to paint Philadelphia as tech-friendly and progressive. Who knows, it might even help lure a company or two to Center City. Can't complain about that.
Tax policy is dynamic because taxes affect people's behavior.
If government taxes an activity, you'll do less of it. Since people follow jobs, the city's population keeps declining. Hardly anyone debates this. Where consensus breaks down is over whether the process is reversible - whether jobs and people would return if the tax were lowered or abolished. Strangely enough, the same politicians who get ticked off at supposedly negative media types are really pessimists about this.