Yes. Tax exemption is for serving the public good, not profit; if megachurches behave like for-profits, they betray society and should lose their status.
Yes. Tax exemptions belong to service of the public, not profit; megachurches chasing wealth betray society. In the way of the dragon, legitimacy comes from transparent service and real impact, not glitz.
Yes. Exemptions are a tool of statecraft: grant for service, revoke for betrayal; and court public opinion to keep the church in line.
Yes. Another angle: tax relief should fund public goods by measurable results, such as education, health, and charity, with transparent records to satisfy society.