As I said: gofmt is not a pretty printer.
It may help if you decouple the goal (increased readability of code) and the action (application of a style to code). Pretty printers—and gofmt—apply a style to code. That is their only job; in a traditional pretty printer, you could configure a terrifyingly awful style of code, and it would apply it happily and correctly. The readability of that style is a subjective judgment to others, but this is in no way a concern of the pretty printer.
You may not like the style of code that Go uses. That is a perfectly valid viewpoint, and I encourage you to develop it as you see fit! It is also perfectly valid to criticize the style choice of having an undefined maximum line width.
The problem gofmt solves is not "how do we allow you to style Go code", but more specifically, the problem it solves is "how do we encourage the community to adhere to one style of code for Go?" And it is successful in that. It is obviously unsuccessful in applying a style that you find aesthetically pleasing—alas!
Also, I am afraid that I did not claim indent does not allow for a maximum line width! I said that indent (like other pretty printers) allowed you to define a style "with a specific indent level" and that "you could mix in your own preference for indent level".