I’m not going to get into the differences in how Protestants and Catholics and Orthodox believe the Bible was written/inspired/etc. That can be a topic for another day (but there are two good posts here). This is actually looking at how much actual, quoted Scripture is used in the course of the Divine Liturgy (and Mass). I found a fantastic analysis of the Liturgy of St. John Chrysostom here (see below) done by the V. Rev. John Matusiak. It’s much, much more than just the Epistles and Gospel. From the Opening Doxology to the Dismissal, the Liturgy is hopscotching all over the Old and New Testaments. You can’t get away from the Bible no matter where you look. There is also a discussion to be found here.
The Catholic Mass too is based entirely upon Holy Scripture (article here).
As for how much Scripture is used in the course of a Protestant service, obviously it depends on the brand of Protestantism and that can be wildly divergent. I am vaguely familiar with what is used in the mainline Baptist churches and a little more familiar with what is used in the Episcopal churches and those are certainly seated on different parts of the spectrum. In any event, this was more addressing the assertion that the Orthodox and Catholics do not base their services on the Holy Scriptures, not about how much the Protestants do.