One thing we know about humans is that, as a species, we were never and are not currently capable of making such collective decisions or otherwise coordinating at this scale. This is probably the root of most problems we have, except death and diseases.
I'm pretty sceptical re claims of knowledge about complex systems, and human ecology is about as complex as systems get. So I think your statement is way overconfident.
Having said that, if I had to make a bet on whether or not we'll make the necessary decisions given how late in the game we've left it, I'd put a decent whack of cash on the prospects of failure. Also that the proximate cause of the collapse of our civilisation won't be global environmental collapse, but war consequent on local collapses. Look at Europe following 2015, convulsions caused by trickles of refugees that were minuscule compared to what's coming. I'd bet on nukes (another can we've kicked down the road for decades) offering the coup de grace.
Complex behaviour of systems often arises out of simple rules. Game theory is not always well applicable, but here it provides some simple models that explain this problem very well: multiple people forgoing individual gains in order to cooperate at getting bigger gains is a very unstable state that can be quickly destroyed by free-riders, who defect in order to reap both individual and group gains. The very awareness of this dynamic, which is something we all have as intuition even if we can't put it in "mathy" words, is enough to severely curtail the ability to cooperate. Looking through this lens, you can discover that of cultural customs and social pressures around individual behavior are really mechanisms that deter and punish defection and strive to establish an environment in which cooperation is easier.
Scott Alexander explored this topic far better than I ever could: https://slatestarcodex.com/2014/07/30/meditations-on-moloch/.
Your guesses happen to be guesses I share. But they're just guesses.
I still hope we can get out of this one, but I don't see the solution coming from "the people". If anything, "the people" will have to be dragged kicking and screaming into that future, by governments mandating the right moves, by public and private R&D creating solutions which companies then use to enable the governments to make the right moves.
It seems to me that only the ultra rich have the resources, independence, and arguably intelligence to lead the way to solutions that could save humanity. They might devote their talents and resources to funding research into technologies we will need when when things get so bad that governments are forced to act. Also funding powerful lobbing groups to counteract the powerful lobbing efforts of corporations that benefit from delaying action on the climate.
I sort of disagree; the governments might be (as usual) the crucial element of the solution - they're the only actors on this planet capable of forcing a decision on masses, even if it goes against the wishes of the market. But getting the government to do the right thing sooner rather than later - that's the hard part. Especially that nations are market players themselves, and doing the right thing in case of climate change means handicapping the whole country on the international market.
I think both the ultra rich and governments can be useful in funding more R&D on clean technologies. The goal here should be developing technologies that ultimately let you go carbon-neutral while sacrificing as little as possible compared to the old methods. Doing the right thing is painful for people, and by extension the governments, so whatever can be done to ease that pain increases the chance that the right things will start being done.
I challenge the ultra rich to put a substantial portion of their assets to work in funding large scale R&D on clean technologies, and simultaneously funding powerful lobbying of governments to act on climate change.
Another thought is that for better or worse we now have the tools for "social engineering" and campaigns might be funded to sway public opinion to support governments that support clean technologies.
I agree with your general point, but I'd add that the market is itself an artifact partly created by government.
I think it's about time we saw more change to the market itself, which requires cultural change among other things.
For example: Insulating homes was mentioned earlier. Yet, more and more people are renting homes and can't do much to improve home efficiency because that's controlled by the landlord, and "voting with your feet" is financially out of reach. Same with working much less, or not commuting: It's not a serious option to those at the less lucky end of the competitive market for essential life goods and services.
Both of those result from a certain style of capitalism, which is arguably in crisis already, and both of those can be greatly improved, even while retaining capital, when there is a widespread change of cultural pressures about basic expectations of owners and employers.
I need to study the details of this case more; from the little knowledge I have on it, the cynic in me would conclude that it only worked as effectively as it did because by the time of the Montreal Protocol, DuPont had figured out and patented a replacement for CFCs.
There is a quite recent amendment to the Montreal treaty, the Kigali amendment (2016), which phased out the CFC replacements with strong greenhouse effects in favour of replacements without them. This alone will save us ~0.3° warming until 2100 (if the projections are right).
This is about the only positive news I've ever seen for this topic.
https://ozone.unep.org/sites/default/files/Assessment_Panel/... (eg page ES.23 & ES.24)
(I really love those charts.)