[pandaman]

>Does anyone know in general why rental properties aren't negotiated further in advance?

Define "in general". All big landlords (Greystar and such) want you to sign lease extension 3-4 months before the current term ends where such thing is legal. There are states that don't allow long term leases past the first term though. For example, in California all leases go month-to-month after the first lease term but they put required notice periods on rent increases (30 days and 90 days if more than 10%).