Unless you live in the sunbelt, it will take more than a few years to recoup. Factor in replacing the inventor every 7 years, it becomes questionable, it also depends on your storage solution or local buy back program. Add an electric car to the mix and it becomes feasible.
But I think it still needs to become cheaper.
It depends greatly on your setup but, unless you are running some crazy, completely off-grid, system with cheap batteries and cheap inverter, you can expect an inverter to last you longer than this. Most are rated for 10-15 years, with some rated for 25 year lifecycle.
As with many things, quality costs, but not all costly inverters are quality, so do your research before you buy.
The warranty for most residential solar inverters is around 10 years, though often prorated towards the end of that timeframe. 7 years does not sound crazy, though with good cooling and and decent quality it's probably a tad low.
