Why would it ever be unreasonable to wonder something?
Of course YANBU. You are, however, IMHO, wasting time and energy on something pointless and inconsequential to your own life BUT you can spend your time how you wish...
there are so many variables that it's doubtful you could have any insight into why this is the case for some. I have a good job and have always worked. I struggle, am usually 'up against it', only holidays are if I visit family, however I do try and go camping in UK once per year. My clothes are old, my shoes are worn till they are too shoddy for work (!), my hair is cut twice per year and I rarely go out.
I am happy and feel truly blessed/lucky whatever you want to call it. I have a DD who is everything you could want for a DD. I have an amazing brother and sister who are there for me always. I had a dad who I've realised sisnce he died 3 years ago, was the most amazing dad ever and continues to be - lots of my friends tell me how lucky we are to have had such a father. I have outstanding friends who are like family.
I would not trade one single thing to have a slightly easier life. Perspective. My dad died penniless (having been a high flyer, private schools for his kids, huge houses, month holidays abroad every year, ponies and horses for his kids, cars for our 18th birthdays - you get the picture) yet he was happiest without a penny but with his soul mate of 8 years.
Perspective.
A family I know from school appeared to have the perfect life. £million+ house, own business, exotic holidays, status cars. Alcoholics, never speak to each other, worked 24 hrs per day, DS extremely unhappy, hated parents, always wanted other ppl around. Now separated and going through very tricky and horrible divorce.
Perspective.
It's OK to wonder sometimes, but it should be fleeting and forgotten. We need to focus on our own circumstances and learn to be happy and thankful for what we have. Took me 40 odd years to work that out but life is better than ever since learning and continuing to focus on what my life is and those close to me. Forget everyone else - we're bombarded about what we should have, what we must have, what we need. Most of it is just 'stuff' and we don't need it at all.
Being happy takes effort and focus - on the right things.
Hope this doesn't seem preachy - really not meaning it that way 