Actually a lot of people did understand quite a bit of the ‘TLM’. One thing about the OF; it may be in the vernacular and have ‘more readings’ but it is also kind of thin. the priest says one of three options, you respond X. It’s very cut and dried.
Some people may find it easy to focus; others become so accustomed to ‘hear A, do B” that they zone out.
The focus is on ‘communal meal’ predominantly.
There is a very ‘outward driven’ aspect. You are told what to do and you do it immediately. There is little chance for you to meditate or to respond ‘in addition to’ what is expected; again, priest says A, you do B, move it along.
Since 2011 Eucharistic Prayer II is slightly better but it is still extremely terse. At least it mentions humility, but the focus is utilitarian as compared to the TLM’s Roman Canon.
While you CAN get ‘smells and bells’, you are just as likely to get Woolworth—Gimcrack felt banners, tie-dye, loud guitars, and bare decor.
It is very much ‘chance’ that any average Catholic can go to an OF and receive the kind of nourishment offered —I emphasise ‘offered’ because it all depends on the person accepting the offering—at any TLM both before and after the OF.
You may say that despite the riches of the TLM, prior to the OF people did not recognise or partake in them. That is true, but it is not the fault of the TLM.
But today though there can be riches in the OF, quite often the priest himself ‘does not partake’ and thus deprives the people, as often as the people themselves do not partake.
As an example, if you offer a 10 course banquet, some people will sample all, some will only sample one course—but they’re all fed (unless they choose not to partake) because there is a wide variety of choice.
If you offer a 3 course meal, some will sample all and some only one but with only 3 choices there are likely to be many who don’t partake of a much more limited meal.
Again, both offer nourishment. And if a person is very fond of one of the choices at the 3 meal option, that person will consider himself well-fed and be astonished that people don’t feel the same.