(1) Too many people on the planet. Not enough jobs for everyone, yet all need to be "supported".
(2) Too much government, all around.
IOW... there is no "fix" to this situation...
Biologist that I am, which includes the study of Population Dynamics... One prominent population dynamics professor states... "planet earth can support only about 3 Billion people in a healthy fashion". If that is actually the case, what are the ramifications and consequences of a world with 7 Billion+ inhabitants? I think we are experiencing that right now.
In "closed populations" (which include planet earth), populations tend to expand to excess... until the population exceeds the ability of the substrate to sustain their numbers... then, EVERYBODY/organism dies because the ecosystem exhausts some vital resource... food, water, space... or the toxic byproducts of life overwhelm every organism and they die. (Think air and water pollution.)
Not saying "every organism on the planet will become extinct"... but the ones with the "greatest requirements for support" will certainly go and likely be first. In the end, cockroaches will rule the earth. Yes, even after the Muslims have also seccumbed.