If batteries have environmental conditioning (that is, they're kept corrosion free and temperature conditioned like tesla does), I'd imagine you're going to find that they will still have a reasonable amount of capacity at 30 years.
I believe tesla's target was about 180k miles in the S to have batteries with 90% of capacity remaining (which I've read tesla considering a good point to target). There was a taxi company in malaysia using S's (why, I don't know - the S has a poor reliability history, but we're just talking about the batteries - maybe the cars are a status symbol). When you read accounts from S owners, the consensus seems to be far more than 180K miles before reaching the 90% target. How far off of 90% does a large battery need to go before it's not useful for household? If you end up with a 75-100kw/hr pack, if it even has half capacity and is still working reliably, it'll be useful.
The next generation of tesla batteries are supposedly good for 1000 full charging cycles, still meeting the 90% capacity target (half million mile battery claim due to this for the pickup, and million for the trucks when they start producing them). If there is a stationary system that can manage the used packs, I can't imagine a market won't organize for them.
The comment above re: environmental, lots of assumptions are involved. I've seen studies claiming 150k miles for environmental equivalence (usually from an org. that caters to the petroleum industry) accounting for all of the components as well as the energy use (that is, the pollution in making the batteries is accounted for). I saw a german study that was a bit more independent years ago where the authors expected to show that battery cars are bigger polluters, but concluded breakeven on pollution around 100k km/ or just over 60k miles.
That will probably continue to improve.
The mistake that we all make looking at this (I don't, but many here are making the mistake) is assuming that looking at a current snapshot of electric cars is something that can be overlayed over the next several decades. I don't think the industry for used packs is particularly large yet, and have seen more FYI videos about disposal of used batteries than recycling. But the batteries will change and if there is economic interest in reuse or recycling, that will, too.
I'd have to imagine that a stationary pack with more gradual demand on power than a car, and steady environmental conditions will be pretty easy to use for a long time.
I got two articles this morning that Toyota and VW will have solid state batteries in use starting in 2021, with more widespread distribution by 2025. There's also huge money being spent in battery technology that was never spent before almost solely due to Musk expediting the initial work and creating demand due to widespread recognition.
As to the comment above about loss of road or fuel taxes. We hear this all the time in the US. Quite often, the road taxes pay for little of the road maintenance here and often have been diverted elsewhere. On top of that, I haven't seen too many governmental entities that aren't good at creating new revenue sources. That whole discussion is just a diversion - if there is a need for revenue, once there is market saturation, it'll be collected one way or another.