Measuring “single developer productivity” is unsolved problem. It also is not a problem unless you are pointy haired boss and want to plan bonuses based on that or fire people based on that.

You definitely can measure team output over time and have some idea. Compare team to what they did in last 6 months and you have your measure for having idea how much can be achieved next month. But you cannot not plan like what can be achieved in longer period just next sprint or two.

This said you cannot compare teams like that.