The equality was to do with service provision, in that if they have a flat rate they charge it should be expected that the service be the same, which I know it isn't, but the point remains.
As for reinvestment, sorry to be the one to tell you this, but in an age where profiteering is rampant and customers are seen as secondary to shareholders, the first thing that suffers is quality. As for the more competition thing, err no. That simply will not happen. You already have a massive market that is shared by a few. Short of Elon Musk buying a horse in that race, any and all smaller alternatives will be swallowed up or crushed before they have a chance to be established.
Btw "cost effective" in the sense you refer to with AT&T had nothing to do with shit service provision or regulation. A choice of one is hardly a choice, and a monopoly doesn't need to provide good service. Its the only service available, therefore there is no comparative template for consumers to make.
Capitalism or free market enterprise is the way to go, no doubt, but to have true capitalism you need choice. The more choice, the better for the consumer. It breeds both innovation and it can effectively regulate itself if there is enough choice. Price fixing is nigh impossible if you have a plethora of options, as someone will always say to themselves " a few bucks off their bill to keep their business with me is better than no bucks at all", but sadly your internet provision is held by some very powerful conglomerates with some very powerful friends and even more powerful lobbying groups, and I can assure you they don't want to share with anymore than they have to.