Well, most of us don't want to HAVE to give it all up, but if one is a true BELIEVER, it's probable that they would. The martyrs of Rome had no problem dying for their faith. It was simply what was done. Christians (and Jews) have died willingly for their faith all down through the ages.
The problem with this kind of martyrdom is that it sometimes sets up a cognitive dissonance in the persecutors and observers. To them, who don't believe (regardless of their nominal "Christianity," in such cases) the DEATH OF LIFE is the ultimate end.
For a believing Christian or Jew, death is just a door one passes through to the REAL life. Now: If there is NOTHING on the other side of death, none of these martyrs knew anything different once they were dead. BUT if there IS eternal life on the other side...
American Christians do not resemble roman Christians. American Christians are affluent, Roman christians were mostly dirt poor (but not in spirit!). But you are right - the TRUE believers would lay it all on the line, I only question the devotion of most Americans who call themselves Christians. Money is king here for most people.