The James Webb Space Telescope will deploy (unfold mechanically) while on the way to L2. Couldn't it do so in LEO, where it is potentially serviceable? Starliner CST-100 and Dragon are planned to soon allow affordable crewed missions to LEO, and Soyuz could maybe already do it. At least Orion is designed to allow for an EVA, and it is a $bn 8.8 telescope. Even if JWST is not designed to be upgraded, a moving part gotten stuck might be moved manually during an EVA. The upper stage would then bring it to L2. I do think some other spacecrafts have orbited Earth before having set off to their interplanetary destinations. Why won't JWST deploy in LEO where it is potentially serviceable? (like Viking?).