In 30 years, percentage of Protestants rose from 6.6% to 22.2%
 
. . . .

In 2000, Protestants made up 15.4% of the population. In 2010, they already made up 22.2%, what represented increase by about 16 million persons (from 26.2 million to 42.3 million). This percentage was 9.0%, in 1991, and 6.6%, in 1980.

 http://www.ibge.gov.br/english/presidencia/noticias/noticia_visualiza.php?id_noticia=2170&id_pagina=1

What is going to happen to a conciliarized SSPX?

It won't be pretty.

Catholics disillusioned with the novus ordo and it's obsessive insistence of subjectivism leads many misguided Catholics with no choice but to jump ship and become protestants.

A lot of people really don't spend a lot of time researching the histories and the theology involved.  They simply see the conciliar church teaching that everybody's truth is the truth but somehow we think our truth is better as "hiding Jesus" and they go into a protestant church that is energetic and fun and the entertaining guy in the nice clothes up front is preaching about "Jesus".  

It's not so much protestantism growing but the continued shrinkage of the novus ordo conciliarists.

This isn't Bishop Fellay's fault.  The SSPX is a small, tightknit, dynamic group but they couldn't counteract the negatives of the conciliarists except to those Catholics who dip their noses into the book and learn more about Catholic theology and practices.