The threat of Non-Net-Neutrality isn't some arbitrary increase in costs for starting a business that gets paid, and filed with other nuisance.
It's that by virtue of their position in the market, the providers can extract all the added value any company makes with their customers. That's because the startup isn't the one choosing their customers' internet access. What the provider charges for access to the customers that signed up with them doesn't factor into the decisions of the market, because the customer doesn't pay it, and likely will never know about it.
And "the market" will not solve this. There are maybe three or four companies large enough to cause significant backlash when they can't be reached. But besides Facebook, YT and Amazon, everyone will have to pay up.
And when faced with the decision to pay or not to pay, the rational decision will be to accept any price that leaves you with a single cent of profit. The power imbalance is staggering, and the potential for success with content startups on the internet will suffer dramatically.
On the practical side, your startups' second to tenth employee better be contract lawyers. Because you don't just have to pay Comcast and Verizon. You will have to make arrangement with every single one of tens of thousands of providers around the world if you want to reach customers connected via their network.
Of course, you probably won't bother with some of them. Or decide against, say, reaching potential customers in Montana. That will kill off several of the best features of the web. Namely the long-tail of default-accessible content that ordinarily nobody would think were interesting to someone of your age in your location.