We already have efficient enough solar panels to make our homes self sufficient, we just can't afford to buy them.
Even if we could, the power supply industry would see it happening, bribe and persuade the government to make it illegal to go off grid (I'm sure their solicitors would come up with "good" reasons that we should be stopped), to save their poor little shareholders.
No way will they go down without a fight. Would I love to go off grid? Sure. If I had a few grand of spending money I could easily do it. But that's just one person, no way they'd let the entire country do it.
There's a very good reason you don't want the entire country to go off-grid, and that net-metering is a plague that only serves as a wealth transfer from the poor to the rich.
A large chunk of electric costs are fixed costs. Wiring, power station upkeep, more wiring, transformers, storm damage, etc. Whether you personally use twice or half as much power as the median household does not matter for this. So every net-metered kWh you send on the grid, everybody ELSE ends up ponying up the infrastructure costs for (nevermind the enormous production-side costs of fighting against the duck curve).
A partial solution to make this fairer is therefore to either tax solar installations, use non-net-metering (with digital meters), or make grid connectivity a fixed cost in the electric bill.
For people who are completely off-grid (meaning not only do they not pull any electricity from the grid ever, they are not connected AT ALL and therefore do not incur infrastructure cost on everyone else), it's not as bad but sill not great because the grid operates on economies of scale. So in (semi-)urban areas it's still a net loss for society when someone goes off-grid.
We are 90% there already. In many states, solar panels and usage have extra taxes. Most solar installations are grid tied and electricity sale prices to the company are fixed at a small fraction of their sale prices from those companies. Worse, if power goes out, you can't use solar to stay electrified because electricity would leak out and potentially electrocute nearby line men.
All mains connected solar has an inverter. Hell, most wind is part or fully converted, to smooth out the raw waveform, and thus is inverter driven.
Where I'm from your "interlock switch" would be called "island mode". It can be a thing, but distribution network operators have a legal obligation to maintain supply (or else they face harsh financial penalties) and as such they are reluctant to allow even the possibility of unintentional backfeed to their network, especially when they need to work quickly to keep supplies up. Safely regulating every single household is just too burdensome, not without extensive modification that no one wants to pay for.
Worse, if power goes out, you can't use solar to stay electrified because electricity would leak out and potentially electrocute nearby line men.
Has this... really ever been true? We've had gas powered generators people can plug into their homes for a rather long time now, and they would be doing the exact same thing as solar installations.
It depends on where you are mainly, but I do believe the kit that prevents what you describe, is functionally mandatory to have for solar. Not certain on that, and it definitely still depends on locale, but I haven't seen any without that lockout in a loooonging time.
Yes any professionally installed solar kit is going to have that liability prevention included with the design. That person is just spouting bullshit from some half-learned information.
I built my own solar offgrid power station, and I didn't install that protection, but it's also a completely off the grid power source so it doesn't matter. I installed a dedicated ground and breaker for it and it works as a standalone power source.
Worse, if power goes out, you can’t use solar to stay electrified because electricity would leak out and potentially electrocute nearby line men.
Your info is a bit out of date. With a single battery you can use nearly any solar system to generate and consume that energy during a grid outage. With a couple brands of gear (such as Enphase IQ8) you don't even need any battery to generate and consume energy from solar during a grid outage. The term to look for for batteryless is called "self grid forming".
Grid forming typically refers to inverters connected to a large electricity network. What you're talking about is islanding, ie running a system separate to the grid when it would normally be grid following. The principles are similar, in that both involve using internal voltage measurements to control the generation output (rather than externally chasing the grid voltage), but the practical nature is different - grid forming systems have to deal with large fluctuations from the network, well beyond what you would see in a domestic system. The terminologies overlap a lot, but grid forming specifically refers to large scale systems and more complicated networks.