I beg the differ. The TLM is gaining souls wherever is being offered, and those souls are reproducing, unlike many of their counterparts in the parishes where only the Novus Ordo is offered. I have personal experience of this.
There is also a problem with ordination of post-Vatican II priests celebrating the TLM. Their orders are disputed by traditionalist Catholic sources.
Only sedevacantists and certain people in the SSPX would dispute it.
We will only know in 10-20-30 years form now. No immediate trend can be prediced. I would say the majoirty of people looking for TLM masses are older than Vatican II with some cuious young people seeking something more dignified adding to their ranks.