Are you deciding "expedition" by duration of the trip or location?
As far as duration goes, what I bring for a two week trip is not much different than on my longest trips of 10, 12, 13 (and counting) trips. Perhaps a few more spares like two tires instead of one or an extra disc rotor.
As far as location goes, there is a much wiser list of countries than "US and Europe" where if necessary it isn't too much of a bother to resupply with something you forgot/learned you need. For example, in both Perú and Western China I acquired a second lightweight sleeping bag after learning temperatures were colder than I had planned. Similarly if necessary, bike shops to be found in largest cities of a much larger set of places.
After that harder to generalize since things like: visas, immunizations, clothing, etc are very location dependent. Within a location, how you travel also differs, e.g. outback Australia on sealed vs. unsealed roads. Time of year matters, e.g. eastern Russia in summer vs. winter. Other factors make it much more important to list *which* location rather than generalize to *expedition* for everything that isn't US, Europe or similar easier places.
Well that makes a lot of sense. Do you have anything to say about having things shipped to you vs waiting until the next large city, like your sleeping bag example.