Its either:
Hotels due to work or other family obligation
Camping with an odd hotel or hostel stop for a shower and proper bed
All camping
More or less, yes, however on our first "big trip" (11 months around South America) we didn't fit any of these. We camped for a week on a walk up Monte Roraima, otherwise we stayed in posadas/small hotels in rural areas, and in big cities we stayed in "good" hotels to have a break, have a good internet connection, and generally take advantage of the facilities. This was principally because in the rural areas you can find good clean hotels for USD 25-30 a night, and it made economic sense to take advantage of this. In Australia hotels are USD 100-200 in rural areas, whereas campsites are USD 25-35 (OK - you can, and we did, "wild camp", but it's not feasible a lot of the time).
So, in terms of these categories:
1) Hotels due to work or other family obligation - yes, we use hotels when travelling on business, however also for short (up to a couple of weeks) trips when we're travelling somewhere we can't reach in our own vehicle, at least on a short trip (e.g., trips in the last while to Patagonia, South Korea, Vietnam, Algeria...).
2) Camping with an odd hotel or hostel stop for a shower and proper bed - haven't yet reached this point on "big trips", although I guess we have occasionally on short trips of a few days.
3) All camping - not for many years.
On our "big trips" we are in what I'll call category 3A - category 3 with more than an "odd hotel or hostel stop" - South America was 2% camping, Africa was 33% camping, Australia was 68% camping.