God said about some of His prophets:
We revealed to them to: Do good deeds, establish prayer and give zakat. And they worshiped Us (by abiding to these rules).Qur'an: al_Anbiya: 73
And about fasting He said:
O believers, We have made fasting obligatory for you like we made it obligatory for those before you.Qur'an: al_Baqara: 183
And He told Ibrahim:
And tell the people to perform the pilgrimageQur'an, Haj: 26
These four pillars, even though they existed, were nevertheless different from how we know them today. The reason behind this? Previous Prophets were sent to their people, not to the world. Their message was never meant to be a universal message but Mohammed's (peace be upon him) message was.
Salah (often translated as prayer) is no longer an action restricted to supplicating and begging as it was for the previous generations. Now it consists out of words, commemoration, recitation, actions, prostration, inclination and directing towards the Qibla.
As you have noticed, prayer, fasting, zakat and pilgrimage although existed from before, their shape and form have nevertheless changed. In mentioning this, I would like to emphasize the fact that these four pillars have always been a God-Given present.