I’m not sure what your point is exactly.
I am not denying that the term ‘terraforming’ can have various, graduated connotations. If you wish to argue that farming is a form of terraforming or that human driven climate change is a form of terraforming, I can see the point. That is not the connotation of terraforming I am using though, and that should be clear.
I think that you may also be arguing that because we have altered Earth’s biosphere it strengthens the case that we can do so elsewhere through a mix of technology and biological processes. I don’t believe I argued otherwise. There is, however, a very large difference between altering a biosphere already capable of supporting intricately complex biomes and ecologies and transforming a planet like Mars into a planet that into one that can support similar biodiversity and complexity.
Would it be impossible to terraform Mars in this grand sense? I’m certainly not qualified to say, but my guess would be that it is possible. My point, to state it again, is that I don’t think that’s the direction humanity will go in. I think that the path of least resistance, so to speak, is the virtualization of human society and mind in general. That path is woven of many unrelated trajectories that are all being followed of their own accord. Just to give a few examples I would offer the building more realistic games and VR media, medical treatments (amputees, neurology, etc.), social networking, AI research, and so on. There is a confluence of myriad smaller paths that are leading toward the virtualization of human society; it will develop organically and without any single entity (i.e. a government or corporation) having to engage in a focused and extensive engineering project. It is simply a direction that humanity is already going in. I think that once we begin to expand into virtual space in earnest, the impetus for things like terraforming will lessen. I’m not implying that it will dissipate entirely, but it will cease to be a necessity for the long term (and we are talking crazy long term here) survival of mind. It will become a luxury that may or may not be realized. You simply don’t need to create planetary biospheres to maintain virtual environments.
I hate to sound like some supplicant to the cult of transhumanism, because I’m not. I’m very far from that, but I can’t see any empirical reason why it won’t happen eventually. It is simply my guess that it will happen before we start terraforming planets or building Dyson Spheres.”