If you have an opinion on this, it will usually be a strong one. People who travel with backpacks see it as a badge of honour, a way of earning the travel experience you are about to have. People that love their backpack have a hard time not travelling with it - like they are somehow cheating by opting for a case with wheels.
I do think that as we age, the lustre of the backpack does fade. Having to pop your pack up on your knee in preparation for the heavy swing up onto your shoulder starts to really feel like a chore and the draw of a wheelie case becomes more and more inviting.
There are times when a rolling suitcase is truly the way to go, such as resort holidays which include airport transfers or cruising, the convenience of rolling your case around and it standing on it’s own during check in and while waiting for transfers make it the best option.
A backpack on the other hand cannot be beaten on uneven terrain such as cobblestones or sand, also many tour companies in Africa insist on soft bags/backpacks for ease of packing into overland trucks. For trekking tours in areas like Nepal a backpack is best but tours in other countries such as Egypt, Israel and Morocco a suitcase is probably more suitable.
It is much easier to navigate stairs with a pack, but much easier to walk long distances with a suitcase. Now you can get hybrid bags which function as both a soft backpack with a frame and the added convenience of wheels, could this be the way of the future? A way for people to pass their fear of moving from their adventurous ‘backpacking years’ and into their holiday years. These bags allow you the pride of wearing your backpack, with the hidden extra of opting for your wheels on tiring days or smooth ground.
Some people will always be backpack people, a few weeks ago I saw a very happy couple in what looked like there 70’s navigating an Italian train station proudly toting their aged and very travelled backpacks, I guess for some people, donning their pack at the beginning of the trip will always be part of their travel experiences.