Is Sedevacantism Delusional?

A reader has written the following on my post of "Is Sedevacantism Heretical?"

"Introibo you have posted rubbish! The heretical position of the sedevacantist is that the Church is going through a great apostasy! Well, this contradicts the very words of scripture..."I will be with you all days...unto the consummation of the world"...the world has not been consumed and our Lord is still with us...as is His Church, which is indefectable and will stand for all time! No where in scripture is a great apostasy within the church mentioned ANYWHERE...not even prophetically or literally. Quite the contrary is mentioned...our Lord says that "wolves will get into the fold"...these are heresyarchs...who have names and obvious agendas. One is to confuse and poison the mind of believers that we are living in a time of apostasy, that the sedevacantists have created! This is in contradiction to scripture and the teachings of Holy Mother Church...who, on matters of faith and morals is infallible...as it must be, in order for the members of the Church to understand what she teaches, in order for us to save our souls... You my friend are not only delusional, but you are a heretic"

I've already dealt with the absurdity of sedevacantism as heresy. So, my opponent's unproven assertion that it is “delusional” to believe that the overwhelming majority of Catholics might one day end up adhering to a false pope, I respond with the teaching of the theologian Father Sylvester Berry:

“The prophecies of the Apocalypse show that Satan will imitate the Church of Christ to deceive mankind; he will set up a church of Satan in opposition to the Church of Christ. Antichrist will assume the role of Messias; his prophet will act the part of Pope, and there will be imitations of the Sacraments of the Church. There will also be lying wonders in imitation of the miracles wrought in the Church.” (The Church of Christ, 119)

“There seems to be no reason why a false Church might not become universal, even more universal than the true one, at least for a time.” (ibid. 155) An ecumenical Super-Church with a false pope? Imitation sacraments? Lying wonders? The faithful reduced to a remnant? After four decades of the Vatican II disaster, how absurd and delusional does that sound?

It is precisely because I believe in the Indefectibility of the Church that I'm a sedevacantist (True Catholic). The Church CAN NOT GIVE EVIL. However, the teachings of the post-Vatican II sect contradict word for word prior Magisterial teachings on what is good and true. Therefore, either (a) the Church defected OR (b) the hierarchy defected and lost authority; the True Church remaining with the Traditionalists. It is through us that His promise to be with us all days stands confirmed.