I've been thinking about this a lot with the current congressional action. I need a new roof ~now. But I have a lingering fear that huge product improvement will happen in the next 18 months due to added government money. I don't know enough about the industry to weight in that possibility.
I'd absolutely do it now. The price of solar has been beneath that of racks, mounts, wiring and installation for a while now. Even assuming a major breakthrough your costs probably wont change that much because panel cost isnt a big % of what your costs will be anyway.
There's also a risk that supply chain bottlenecks/cold war with china will drive up the cost & your electric bill is only gonna go up.
Agreed, do it now. The cost of panels in Australia is already going up due to supply issues thanks to covid, and I don't think you'll see prices come down again for a few years even with that investment.