These are just some of my observations of the first country other than the US where I stayed for a significant amount of time.
Some old men can still found pushing small carts selling sandwiches, but they are rare. Hawker centers are very popular and very cheap. Hawker centers are like food courts. They are called hawker centers because the proprietors of individual stalls used to attempt to harass people into buying their food. Thankfully, this practice is now banned and only practiced at a few of the older hawker centers. Usually there is one shop in the center that sells only drinks. Hawker stalls do not supply napkins, so you have to remember to take your own. It is possible to get a good meal in Singapore for a couple dollars. Many people eat out rather than cook, because it isn't significantly more expensive.
There are more malls, restaurants, and hawker centers in Singapore than you can imagine. Practically every office building has a mall on its first few levels. Practically every mall has a few restaurants and a hawker center.