Why don’t all Muslims adopt the Salafis’ methodology?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu 'alyhi wa sallam, is His slave and Messenger.

The only way a Muslim can ensure his safety is to adhere to the Sharee'ah, as understood by the Salaf (righteous predecessors). Allaah the Almighty Says (what means): {And the first forerunners [in the faith] among the Muhaajiroon [emigrants] and the Ansaar [their helpers] and those who followed them with good conduct - Allaah is pleased with them and they are pleased with Him.}[Quran 9:100]

The Companions understood religion the way that Allaah the Almighty meant it to be understood, for He Says (what means): {Allaah has promised those who have believed among you and done righteous deeds that He will surely grant them succession [to authority] upon the earth just as He granted it to those before them and that He will surely establish for them [therein] their religion which He has preferred for them and that He will surely substitute for them, after their fear, security, [for] they worship Me, not associating anything with Me. But whoever disbelieves after that - then those are the defiantly disobedient.}[Quran 24:55]

The majority of Muslims are followers of Ahlus-Sunnah Wal Jamaa‘ah.

And Allaah Knows best.