"And that's the problem: will smart TV technology ever take off when television makers, even those promoting multi-vendor standards, insist on minimising the compatibility between one year's TVs and the the next"
Simple answer - no.
TVs are not high churn items and users expect them to last a while. The ongoing digital changeover is the only reason they have had to upgrade their televisions for a long time and even with this change, many users are just purchasing a digital set to box and plugging this into their existing television. The move from CRT to flat panel (mainly LCD) is not a forced change but one that is seen as desirable especially now they are commodity items and ever supermarket possible is offloading cheap me-too but perfectly adequate quality systems for low prices. A large percentage of these users also took the opportunity at the same time to switch to High Definition now the standards have settled a bit and the rampant stitch-up of early adopters has passed.
As for consumer satisfaction with smart TVs - from personal experience I don't know of any, especially non-technical, user that is happy with them. This dissatisfaction is either down to awful EPGs and interfaces riddled with adverts, many models missing features such as iPlayer, c4Player and other popular catch up services, through to unstable or just slow to start systems.