It is so much easier to have an invalid Novus Ordo Mass, compared to a Tridentine Mass.
Just for starters, the Novus Ordo encourages "individuality" and experimentation on the part of the priest, which totally opens the door to invalid consecrations, depending on what the priest chooses to do that day. For example, invalid matter for the sacrament -- or invalid form.
The devil is real and he exists. I'm sure he hates the TLM and he conspired to get it reduced to a rare event (after Vatican II) for a good reason.