Time, the omnipresent constraint in life ;-).
I think it's great to work within the constraints of what you have. Buying your way to the top is easy. Anyone can simply pay for all the equipment to take the best images, but it takes talent to make use of what you have. I believe digitalrevtv on Youtube had a series where they took professional photographers and gave them rubbish to work with and the result was often quite incredible.
I wonder how much digital large format would cost? It must be hundreds of thousands, simply judging by what medium format digital costs.
For travel, I often like to take some really simple stuff, often even just a basic kit lens with a wide zoom range. If I want more varied equipment the most I'll take is 28mm, 50mm and either 80-200 or 135mm. To me those four lenses cover almost everything one would want to photograph. Since the Fuji XT-10 has about a 1.5x crop factor I'll often just take the 28mm and 50mm (when going purely digital) giving me a 42 and 75mm equivalent, which leaves very little to be desired.
I resteemed your philosophy post and will be writing my response soon.
I'm really enjoying how this conversation has been progressing. A really fruitful exchange!