No, the keys will last just fine. Ofcourse nobody can answer whats going to happen in the future But if your intentions are just that (buy one, never extend, grab all you can), then why bother at all? You have SLIC activation of Server software and Win8 activates just fine with KMS
True. I had a Technet subscription that expired in 2011, just before WHS 2011 came out. All the Keys from my subscription still work and activate, but you can not get new keys for new products that came out before your subscription expired. If you have a spare WHS 2011 key, that you don't plan on using, I could really use it.