FierceWireless has a relaistic analysis of LTE on their website:
The adoption of 4G wireless and Long Term Evolution (LTE) network technology is a long way off and will probably not be adopted on a large scale by network operators until around 2015, according to the host and panel participants at Andrew Seybold's Wireless University, a co-located conference held in conjunction with the CTIA Wireless IT & Entertainment conference in San Francisco.
If LTE technology does come online, Seybold said, it will be at hotspots where there is an incredibly high demand for data, pointing out repeatedly that for carriers voice services still pay the bills and data does not.
Though LTE may provide 30 percent to 40 percent greater network efficiency in a 10 MHz spectrum over HSPA and EV-DO technology, Lawrence questioned whether or not that was sufficiently efficient to justify a multi-billion dollar investment in an entirely new network when 3G technology is just hitting its stride.
Even though this article does not paint a very rosy picture, I think its prediction is more on the conservative side. In earlier posts there is a mention of 32 million users by 2013 and even nationwide (USA) rollout by 2014, but they are not far off from this analysis. Considering that there are already over 3 Billion users expected to become 4 Billion by 2012, 32 million is not a very big number. There could be even more than that even in the hotspots.
The main thing that needs to happen now is for some operator to take the 'giant leap' of moving to LTE once its available. NttDoCoMo would definitely do that but is there anyone else willing to do the same?