Secular materialism - which has for this half century become the mainstream form of socio-political Leftism - used to 'offer' the promise of making this mortal life more meaningful; by putting it first and with nothing else to dilute it.
People who 'lived-for' some other goal, some 'secular goal', then were able to put these goals first - whereas previously they had been subordinated to religion.
Some of these goals were relatively noble and high: Art for Art's sake was a battle cry of the 1890s, among artists (literary, musical, visual etc) who proclaimed that they were pouring their primary life-energies into art.
They shrugged off the constraints of religion. Some of these vocational, religious-art-ists were geniuses who achieved at a very high level, albeit at the cost of making modern art a more elite and obscure phase.
The same was seen in science; where scientists discarded the Christianity (or Judaism) in which they had been brought-up; and placed Scientific Truth as the highest goal in life; not to be compromised by religion - and some of these men were among the great geniuses of science.
Much more common (especially from the 1960s) were those who discarded religion-based moral systems - to enable themselves (and, they claimed, mankind) to pursue happiness and pleasure without external interference or inner guilt.
This worked for a while, but was never successful over the long term - leading to habituation, misery, addiction, illness and (often) early death.
Political leftists claimed that Christianity stood in the path of full socialism, feminism, antiracism, environmentalism (or whatever) - and claimed to put one (or, incoherently, all of these) of these as their prime value - replacing Christianity.
The general idea of setting-aside religion to focus fully on Real Life (on 'making this world a better place') remained a common justification in The West for discarding, even suppressing, Christianity.
All this was revealed as false by the events of 2020 onward.
Then essentially 'everybody in the world' - including the apostles of Art, Science, Hedonism and Leftism - discarded their (supposedly) highest Life values on the basis of the faked birdemic. They instantly and eagerly believed that to 'save' the world from the birdemic entailed degrading or destroying every this-wordly life priority and value; if 'necessary' forever!
Those who argued that This Life was everything - hence primary - simply gave-up This Life - apparently in order to...
Well, what exactly?
Give up Life to... 'save life'; degrade and destroy all that (supposedly) made life-worth-living in order to... 'extend life'...
But then: What are these saved and extended lives supposed to be For?
Once every-thing of value in this mortal life has been suspended without limit - then (for the mainstream atheist-Leftist) there is no reason to save or extend life.
So... This is where generations of focusing on This Life Only have led us.
To a world where, whatever your supposed reason/s for living; when it came to the crunch none of them mattered - and you simply stood-by, lifted not a finger; and placidly watched them all deleted (potentially) in perpetuity.
Such is the consequence of that chronic, pervasive demotivation which was the unavoidable result of deleting God, disbelieving creation, denying the spiritual, and discarding the real values that these underpinned.