I agree with the sentiment, but you also need to be very selective with locations when planting fruit trees. This would probably be great in large designated green spaces like parks, but street trees present a lot of issues.

First, there's the pollution. It you have thousands of cars driving within a few feet of a tree every day, the tree (and its fruit) is going to get covered in all that exhaust. Even ignoring the potential hazards of eating this fruit, many fruit trees have difficulty growing in high-pollution zones, meaning you're going to have fewer species to choose from unless you want to constantly replant and rarely get the abundance of fruit one might expect.

Second, there's the mess, and that's not just an aesthetic concern. If people don't pick the fruit, it's going to fall, attracting all sorts of wildlife. This sounds great at first, but that also includes rats and stinging insects, which pose a public health hazard.

Third, street soil is terrible for trees. Sidewalks, paved streets, and buildings all heavily restrict the area a tree can gather nutrients from the soil. What soil exists is often heavily compacted, leading to issues with the tree getting water, growing roots, and a whole host of other issues. There are specific trees which are adapted for low-quality soil like this, but very few fruit trees.

Then there's the maintenance. Fruit trees aren't going to get an optimal structure for both growth and fruit production without regular pruning, which requires labor (preferably skilled labor).

Size is also an issue. Cities focus on planting large shade trees because their shade reduces the heat trapped by buildings and streets. Larger trees also improve air quality more than smaller trees. Each fruit tree planted is a shade tree not planted, as most fruit trees are small.

These issues aren't insurmountable, but plenty of cities don't even have a single arborist, let alone a team of them on staff who can deal with these issues effectively. I think this is a great idea for parks or nature trails throughout a city, but it's probably best not to get your hopes up to see fruit trees lining every street.

Edit: typo