[pavon]

Eventually we'll have equipment on Mars that we want to function for a long duration, and we'll need to solve that problem, but for InSight (and others) death by dust was by design.

It costs money to operate these probes with a whole staff here on earth monitoring, commanding and analyzing the data that we receive. After some time you get diminishing returns on how much you can learn from the same probe, and would be better off paying these people to work on a new probe (improved using what you have learned) or even an identical probe, deployed elsewhere on the planet.

When these missions are designed that is taken into consideration to determine the desired lifespan of the mission, and the probe is designed to that lifespan (with some margin). Spending money (or worse mass) to make a component survive well beyond that lifespan would be a waste, and could cut into the (fiscal or mass) budget resulting in tradeoffs that make the probe less capable during the lifespan it has.

Insight was designed to operate for at least two years with margin. It has hit the limits of that margin after four years and it's time to shut it down.

[malkia]

Well said. Never thought about it from this perspective.

[b112]

It's all true, but times are changing. Soon it will be cheaper, as lift cost drops, to just send a thousand cheap, heavier probes towards mars... than one super engineered probe.

[SAI_Peregrinus]

But with a thousand probes you still might not care about dusting the panels off. It all depends on how long you need the probes to last. Mass savings will still be important, in the same way material costs become more important when mass-producing something than when making a one-off.