After having 3 kids and going through a lot of strollers I can answer that a bit. A way to make a big improvement for yourself and for others is to buy the $50 basic stroller. Not the $500 "full-featured" one. Far better everywhere, and far more considerate of everybody else on pavement, public transport and everywhere else.
You'd think that a $500 stroller would be better, but after trying 3 of those it's just not true. A $50 one folds up to the size of large umbrella, and weighs 2-3 kg. A $500 one folds up to the size of a suitcase, weighs 20-30 kg. Even folded out they're smaller.
So it should be pretty obvious that a $50 one is far, far better anytime you have it with you and aren't using it as a stroller. Which is really quite often : in the car, on stairs, anywhere you're expected to sit down (from parties, at friend's houses, even cinemas). And truth be told, they're better when you're using them as well. They don't roll as nicely, but they're so much lighter. Also, you have zero issues with breaking them.
Assuming the stroller is synonym for a pushchair/buggy then the best alternative IMO, unless the parent is infirm in some way, is a sling and backpack.
