Completely agree. Hence why I hold to the Cassiciacuм thesis.
Yes, Cassiciacuм makes perfect sense and solves nearly all the legitimate difficulties with straight sedevacantism. Father Chazal's position is also strong ... and only different in subtle nuance from sedeprivationism. Father Chazal emphasizes the material possession of office, whereas most sedeprivationists emphasize the formal vacancy. But it's just two views of the same thing. Bergoglio (et al.) deprived of all teaching authority while remaining in possession of the office and possibly some aspects of jurisdiction (able to make appointments, etc.) If Bergoglio can make appointments and those who hold the office can have formal authority if not impeded by their own heresy, eccelsiavacantism problem with (objection to) SV completely evaporates.
NOTE: Father Chazal denies this because he does not want to be seen as "sedevacantist", but I have seen no convincing argument that his position is any different other than in emphasis. In his video introducing Sede-impoundism, he emphasizes that Bergoglio is indeed a manifest heretic and thereby is impounded and has NO authority, that he can and must be entirely ignored. Classic R&R holds that he still has authority, which must be obeyed when it's not in opposition to Tradition. It's more of an
ad hoc disobedience to specific commannds, whereas both SPism and Sedeimpoundism hold that he categorically lacks the authority.
Both classic R&R and (what LOT called) "pure" Sedevacantism have legitimate serious issues, which these groups have been fond of pointing out about one another. SPism solves both sets of complaints. Beside that, Bishop Guerard was a if not THE top theologian in the Church prior to Vatican II, so I love it when people attack him and characterize his theory as "idiotic". Nor did he invent the formal vs. material distinction regarding the papacy; it can be found in St. Robert Bellarmine and many other theologians.
I actually believe that Archbishop Lefebvre was closer to impoundism than to what R&R has morphed into. He emphatically stated that this degree of destruction cannot happen, since the Papacy is guided by the Holy Spirit (which most modern R&R reject), thinks SVism is possible, but defers to the Church for the final solution and filled with hostility toward the other side, often moreso than toward the Modernist occupiers of the Church.
When Father Chazal came out with his position, I was hoping that it might be a bridge between the SV and R&R camps, but it hasn't worked out that way as many SVs and R&Rs are dogmatically entrenched in their respective positions.