One can "get started" with unpredictable renewables, and they are certainly extremely beneficial as they displace fossil fuels in the generation mix. 10% or 30%

One can "get started" with unpredictable renewables, and they are certainly extremely beneficial as they displace fossil fuels in the generation mix. 10% or 30% of yearly energy coming from renewables is great already. Some gas or hydro that has already been built can be used to flatten the worst peaks and valleys etc. But once renewables go to higher percentages, the issues get worse. The main problem is that energy storage is currently very expensive and still dependent on geography (hydro power). So the electricity price will crash when it's very sunny or windy. That hurts the profitability of solar or wind power. Like you mentioned, we would need to invest hugely in long distance ultra high voltage transmission lines, load buffering like green hydrogen for steel making, green concrete etc and maybe ultimately even batteries. These are large investments. Changing from fossil fuels takes a lot of money. The steel produced this way is more expensive than coal or natural gas based steel. So renewables have a compensating effect. On the other hand as technology develops, they get cheaper - but when their penetration increases, they also become more expensive since they require bigger infrastructure changes. Yet we still need to do this one way or another. Your new car or house will be smaller and more expensive because of it. Your electricity or heating bill will be more. The sooner we admit that yes, it will cause a lower material standard of living in the short term, but we still need to do it for the long term, the further we get.