There are successful equipment manufacturers; my favorite is Ubiquiti Networks. They're competing (directly) with Cisco's wifi business. Cisco's carrier-switch side is, in turn, competing with Alcatel-Lucent, the traditional supplier to AT&T.
As for carriers, the important pieces to the equation are bandwidth, distance, and coverage. In the United States you need all three, because we have a lot of people spread out over a lot of space. There are 400 million people in this country. Traditionally each of them is connected to a telephone central office, where the equipment lives.
You see all these little dots? http://en.wikipedia.org/wiki/File:Central_Office_Locations.p... Each one of those is a building with at least a few hundred (and sometimes up to a hundred thousand) subscribers connected to it. Each building is a data center of sorts, sitting on land that had to be bought, containing equipment that needs maintenance occasionally, and getting power bills that need to be paid on time.
Many of these dots, particularly the isolated ones, are served by only one carrier, AT&T, who then leases out bandwidth to their competitors because the federal government requires them to do so as a condition of the antitrust settlement in 1984.
Universal service means you're connecting every last one of these dots to each other dot, and with sufficient bandwidth to make that work. Wifi doesn't have that kind of bandwidth, and it's not efficient anyway. The best way we currently have to do this work is optical fiber, strung between poles or plowed into the ground.
I'm not saying it shouldn't be done. I'm just saying that any "startup" who goes at it will need to be well funded.
As with everything it's the last 10% that takes 90% of the effort.
Or in this case the last 20-30% depending on how small you define "city".
The 2000 census found 58% of the US population living in "urbanized areas" of over 200,000 people and and 69% in areas over 50,000. [1]
So, even if you have blanket coverage for every urban/suburban area over 50,000 population, you still have over 30% of the US population to cover. [2]
Even AT&T with its existing investment has to be compelled by law to provide services in these areas where it is not economically viable to do so. The "Universal Connectivity Fee" on your telephone bill helps compensate for the losses. [3]
So, until either high-bandwidth long-range omni-directional wireless becomes portable and energy efficient or the government requires/subsidizes universal coverage, alternate technologies are not going to go beyond boutique "alternatives" for urban folks.
[1] http://www.fhwa.dot.gov/planning/census_issues/metropolitan_... [2] For example, Southwest Bell had to set a number of poles and string over a mile of cable to my parent's house. We had friend where that run was over seven miles for a single customer. [3] http://transition.fcc.gov/cgb/phonebills/samplePhonebill.htm...:
Hint: It's not twilio. It's companies like AT&T, Level 3, Amazon, MS, etc.
With AT&T goes the data, even if you haven't had a 'phone line' in a long time.
There's a reason wireless companies have been fighting vigorously to avoid becoming dumb pipes.
That's like saying you it's better to own a website, rather then own Amazon EC2 or <insert any datacenter here>.
Twilio doesn't actually move any data from here to there, physically. AT&T will actually pick up your data here and take it over there. They're the ones who've done the work of laying fiber across the country and putting up cell towers so that communications can actually happen. These things cost money and can't happen overnight.
Twilio is a reseller. They may be a really good reseller, but they are reselling service and a decent amount of the money paid for that service still flows to AT&T (and the other carriers).