In other regards, your correspondent is quite correct. All Reformation churches removed as much Latin as fast as possible.
In a way, it is clear that the promise regarding the 'gates of Hell' applies to the Roman Catholic Church--because we have seen those gates (especially in Milwaukee) and have not yet disappeared.
The arrangement of the sanctuary of a church is hardly "the gates of Hell."
The Novus Ordo is hardly "the gates of hell" (though the SSPXers would have you think to the contrary).
I belong to a vibrant parish with 10,000 members, about 6,000 of whom come to Mass every Sunday.
I just can't imagine retrograding to a Tridentine Mass in our parish. That act alone would simply kill it.