That is the absolute worst case of what non-net neutrality world would entail. What the telecoms have been trying to push, and what google is completely against is not blockage, but tiered access. Such that the packets from a company such as microsoft.com would be given higher priority than the packets to another company, say youtube.com (this of course would depend on your carrier and what those end sites payed to the intermediate carriers). Those packets to youtube would still get to where they needed to go, but with higher latency, and thus lower overall throughput. There is this great fear that that would make smaller sites unable to compete, however if this were to become the case, it would create a market for "network co-ops", eg sites could easily pool together to get their packets in the highest priority tier.