Terrans don't seem to have that many all-ins these days. I give the example of morrow vs idra in the IEM finals, morrow pulls all his scv's with his army to kill idra, his attack fails, but his income is higher than IdrA's from mule calldown. cool.
anyways yeah it's a FE as protoss, while pumping units out of 1 gate till you can get the expo up. around the time it' nearly complete you have 3-4 gates, and when it finishes you can then transition into normal 2 base play, ie 6 gate + tech, or whatever. That then allows you to pull ahead in food count from being behind.
The risk though, is surviving to get your expansion up. if the terran attacks early, or throws down a magical all-seeing-eye-scan then they'll probably just walk over to your base and roll you.