Well your looking at it wrong. Take any given tower, if that specific tower gets busy, the 5% of users that are/have (not sure what the criteria are) using the most bandwidth will be throttled to ensure that the other 95% still get good speeds. Its pretty rare on 3G at this point (in my market), and I would assume 4G has enuf headroom to avoid the issue there for a while.
EDIT: Looked up the specifics, looks like they only throttle 3G Unlimited subscribers who fall into the top 5% of all data users. With the raw speed that 4G gives, Ill bet very few 3G users are still getting the throttle.
Also, quote from Verizon : "The difference between our network optimization practice and throttling is about network intelligence. With throttling, your wireless connection is slowed down for your entire cycle, 100% of the time, no matter where you are. Network Optimization balances the best possible experience on the network and for the customer. Network Optimization Practices is more precise and requires more management than throttling, however it provides the greatest balance for everyone. So, if you’re in the top 5% of data users, your connection is slowed only when you are in a congested cell site."