I'm not (at all!) qualified to speak to the situation (transformative or not) in Ukraine, but historically, a single external threat (particularly an existential one) can change society. The prime example I'm aware of is the change that happened in the US when the Japanese attacked Pearl Harbor. In a more minor way, I've seen people come together during blizzards.

That said, other than Javelins, a few HIMARS, and a sole Patriot system, the West has been providing weapons already in storage depots where they're very unlikely to ever go into service again, so there are costs associated with safe storage and eventual disposal. The expense of handing these to Ukraine seems to have been primarily one of transport. I'm unclear as to whether the reluctance in sending more modern weapons systems might be one of not-unreasonable caution with a nuclear opponent or one of transitioning from systems that are essentially free to give to active ones that have a substantial replacement cost.

Either way, more and more modern weapons could save Ukranian lives - and I very much agree with the 'peace now at any cost' people that ending this as soon as possible is important.

I'd agree that Russia was taken by surprise, but just given the number of new weapons systems being developed here (not a secret, just read the publicly available Congressional Record) would indicate that there are depots filled with the previous versions. The US has always made a point of 'trading gold for soldiers' lives' - the older systems are NOT going to be sent in to battle when a newer one might lower casualty rates.

Sorry to go on...