That's actually not true. The "big boys" use tons of plugin synths. Hans Zimmer comes to mind (the entire soundtrack to Nolan's Batman series was done with U-he's Zebra2, which is an amazing synth).
What you tend not to see are large-scale touring bands playing live with plugin synths. This is mostly from fear - that something will crash. There are gazillion of smaller bands performing live with Ableton Live and its own plugins, along with 3rd party engines.
What you tend not to see are large-scale touring bands playing live with plugin synths. This is mostly from fear - that something will crash. There are gazillion of smaller bands performing live with Ableton Live and its own plugins, along with 3rd party engines.