A big part for accounting that you have to pay attention to is that you're moving the maintenance from the dimmer rack to the fixtures themselves. Yes, dimmers are pretty rock solid items, but every once in a while they need some pretty major repairs to control or dimming cards. Most facilities will drastically reduce that cost, or possibly even eliminate it. That helps a great deal to offset the maintenance cost on the fixtures.If the pro fixtures don't last 10 years we're going to have some very upset people. FWIW I've had 6 colorforce 72 bars in the air, powered on 24/7/365 for going on 6 years, and have yet to have to do a single thing to them. I expect a comparable ETC LED fixture to do the same.
Its one of the things when discussing LED fixtures and things like automated rigging that needs to be discussed. My venue is running on 1970's dimmers and half our lighting fixtures are from the 80's (strand century 22xx). Its a hard cost accounting problem to deal with. Lights now need to be viewed more like PA where after 10 years it simply has to all be swapped out. Used to be you spent the money on a dimming system that could stay with a building for decades with little maintence... now spend less upfront but way more long term. Its a good tradeoff because what you can do with LED is huge. Not to mention hvac, distribution, gel, lamps, etc.... but... bean counters won't like the "we need a million dollars of fixtures every 10 years".
I also think we are reaching peak brightness that is usable with LED fixtures. Ya, they can get brighter... but they really don't need to get brighter. Even the 1,000 bucks chauvet LED fixtures are stupid bright and brighter then any conventional they would replace. So, hopefully that starts driving down the cost. We're no longer at the point where going LED has any sacrifices. I don't think you need to plan for obsolesces like you did 5-10 years ago.