Not having kids is a selfish modern human construct. Throughout the history of the planet biological organisms have multiplied for a variety of reasons. Species survival obviously. In most cases having a sustainable community means work being continued uninterrupted (whether constructing a place to live, creating or storing food, etc) It also means species resilience to things like disease, genetic deficiencies, being hunted for food (or for humans attacked for power)
Throughout millennia, by way of human invention, humans have reduced many of these necessities. Most recently through the industrial revolution (maybe even arguably through the computing revolution with computers and what we traditionally called robots), humans have almost eliminated the need for large numbers to contribute directly to our well being, health, safety, etc.
Centuries ago your "quality of life" was improved... because you had property that needed tending.. likely a farm.. or a store.. and the ability to hire someone virtually didn't exist.. because THEY had property that needed tending, so on and so forth.. kids were a way to, much likely my first paragraph, ensure that your immediate community (i.e. your family) could be sustainable.
Is it wrong to not want to have kids? Well first objectively speaking it is selfish. And that isn't said with a negative connotation. Biologically it is our role in the species to propagate, for all the reasons stated above. Beyond that it is out NATURAL INSTINCT to propagate. That is why almost all humans (organisms really) are drawn to sex. But in losing our value as individual contributors to our species.. many of us have filled our lives with other distractions, pleasures, etc. So yeah... kids would interrupt that.
But still, is it actually wrong? The philosophy behind it is highly subjective. Basically which side of the issue do you sit on. If you have kids, that seems only normal. If you don't have kids and enjoy your life, you can't see how having kids (and that changing) would be better.
Fortunately.. it will pretty much all work itself out. As cultures stagnate or decline in population, the culture recedes. Less people means less buying, less money flowing in, less free time being spent on things not directly contributing to the advancement of the species, your own personal well being, etc. And as this happens the thought on propagation shifts in the other direction. Whether through boredom, a lack of fulfillment, or really just good old biology kicking in and changing the perception of having kids from a positive to a negative..
We will probably never get to a time again where there isn't a sizable chunk of humanity who doesn't want kids. Modern life is relatively problem free enough of the basic social necessities where the primary reasons that species propagate to begin with will never concern us again (at least not without some extinction level event). So yeah.. for the foreseeable far future.. as our populations grow you will probably see the percentage of people not wanting kids grow.. and as our populations shrink, you'll see that percentage of people not wanting kids shrink as well.
