One size does not fit all. Some commute on flats, some commutes have long climbs or multiple shorter climbs.

Also, most commuters are dealing with lots of stop lights and stop signs. Assuming you do actually stop at lights and signs, getting back up to speed starting in the 50 ring is not exactly ideal. Let's say you're cruising along at 17 mph on the flats in 50xwhatever, now you have to downshift several gears approaching the stop. Then you start back up, reversing the process.

If you downshift to 34 approaching a stop, then you have to shift back up to 50 after the stop.

Let's say you don't downshift at all. Now you have to stand and grind out a big gear to get back up to speed--which is really hard on your knees.

This yo yo process is a pain in the ass. A middle chainring of 39 is much better than a 50 or 34 in my opinion. Even a single ring 42 or 44 might be better than 50 or 34.

50/34 has all sorts of problems. The lower gearing is far more inviting for beginners and out of shape folk who want a road bike compared to 53/42 or 39, so I understand the logic behind it for marketing purposes. But once you get out on a flat road, running out of gears on 34 or dealing with larger gaps between cogs on the 50, can get frustrating.

Also, I find the 50 ring significantly noisier than the 34, which is a bit annoying as well. I've gotten used to it, but the silence of the 34 ring is quite appealing.

I think a wide range 1 X 13 speed, or triple with existing 8-11 speed, makes more sense for both commuters and road riders than a 50/34. Triples are seen as uncool and cost more and 13 speeds aren't around yet, so everyone just works with various compromises.

Oddly, sram has decided to try to sell their single ring system for $1500+, despite dropping a chainring, and the left brifter: save manufacturing costs and increase price--makes sense for them, not the customer.