Not very hard; there are several spiritual traditions which emphasize detachment from objects, e.g. Buddhism. But unfortunately, Buddhist countries don't generally do well militarily because of the focus on monasticism/pacifism. India was majority Buddhist in 6-7th century and arguably that made them vulnerable to the Arab invasions. Similar case can be made for Tibbet.
But this always gets framed as changing the hearts and minds of regular people. Well my own prime minister was a bit upset that people were consuming less during the height of the pandemic. They wanted people to get back to “supporting small businesses” ASAP.
Economists say people have infinite wants and needs but really, in practice it boils down to a desire to constantly learn new things. The only reason why people may want an infinitely high amount of money ie. infinite wants is because there is no opportunity cost to holding money, humans really love having infinite free things and hate things that cost them something.
What's irrational about it?
Especially in this case. People are being asked to drive less, when driving is currently a necessity in their daily lives. Meanwhile the upper class is flying private jets around.
Being asked to accept less in that situation should make you angry. And it isn't irrational.
What we need as a civilisation is people wanting less of everything, but that's really hard. People take things as given and if you even suggest taking away those things they get irrationally angry and dig down even harder.