Price History is shown when there is data for that house - I see it on listings all the time. It is possible that the sales data is not shown form some houses when they are brand new or the last sale was a long time ago.
Individual listings used to have a history of the asking price for that specific property. That seems to be absent now. That is unfortunate because it was one of the features that distinguished Trulia from other similar sites.
We haven't removed any of this information from our site. I'm not sure where you are looking or what specifically you are searching for, but you can see recently sold homes and local market data for this area via the links below.