A quick preamble before I begin, I've never seen the M2, so don't know its exact condition: how it is during rush hour, how much traffic moves on it, etc etc etc
But I strenuously disagree with this sentiment. Infrastructure investment, which includes building good roads, is perhaps the most essential tool in developing an economy. It is via roads through which almost all economic activity happens.
You travel to stores, and other leisure sites via roads. Goods move via roads. Services move via roads. With the exception of purely digital products & services (which are rather limited here), all economic activity happens via roads. But much more importantly, transit time plays a huge factor as well: if you have wide open roads which reduce travel time, along with the massive headache associated with traveling, Pakistan's economy will boom (shipping twice as many goods in one day, having twice as many people come visit your store becuase of easy access).
On a purely anecdotal level: there are so many times when I hold on visiting stores and doing other economically positive activities simply because of the spectacularly pathetic roads here (in Karachi at least). Whenever anyone in my family wants to go somewhere, we always look at the clock first...and that includes grocery runs because everywhere here is incredibly congested. So from my personal expereince, if the road network was better, I would definitely be contributing a lot more ot the economy.
The frustrating thing in Karachi at least, is that it has a somewhat acceptable infrastructure. The problem is enforcment. You have people in stalls who encroach on to roads, reducing a 3 lane avenue, into just one functioning lane. Double parking, various animals, stupid buses taking up two lanes when they stop, absolute morons who don't realize that they can save more gas if they drive smoothly instead of driving the wrong way on a road becuase it's 30 seconds shorter.
Sigh, I could talk about this forever; but seriously, if you really want to help out our economy, improve our roads (and as a corollary: your behavior on these roads).
That's not to say that other things you said aren't important, they are. But I would argue if you fix roads, you can fix all those problems (including drinking water as strange as that sounds).