Yes, It's a Myth

Jeff Ostrowski mentions a persistent falsehood.

The Catholic Church before Vatican II focused on externals, never stressing a personal relationship with the Lord. The priests rushed through Mass as quickly as possible—to get it over with—which made no difference because priests in those days didn’t understand the prayers (recited in Latin). Low Mass often lasted 15 minutes, and the Requiem was frequently chosen because it was shorter; not because of the priest’s sincere desire to offer prayers for the dead...

Jeff questioned a few friends of his who celebrated "pre-VII" Masses and all of them stated with no qualifications that the allegation(s) are lies.

FWIW, I was present for lots of those, too--and there is no truth to the "15 minutes" thing at all.  There was no sermon, of course, and few communicants* (these Masses were held at 6 AM)--so the time taken was naturally less.

As to the 'preference' for the 'shorter' Requiem Mass?  Another marker of ignorance.  Those Masses were said because of stipend-offerings made by relatives or friends of the deceased soul for whom the Mass was offered.  The priest was obligated to say the Requiem Mass if he took the stipend (usually $5.00 in those days.)  Had nothing whatsoever to do with 'brevity.'

These days, we all know that every soul is immediately granted entry to the Beatific Vision, of course, so there's no need for intercessory Masses.  Right??

*This brings up another discussion. 

When the 6:00AM Mass began, there would be a dozen or so people in the church--but at 6:20 or so, another dozen would suddenly appear at the back of the nave.  They were "daily communicants" who did not attend the Mass, but wanted to receive Communion. 

Just before the communion of the faithful, the altar-boys would recite the Confiteor, and the priest would turn from the altar and give a 'short shrive' consisting of two prayers.  That ritual is the "third Confiteor"  which was inserted in the EF Mass specifically to accommodate those "daily communicants"--and which was removed from the Mass just before the 1962 Rite was codified.