It's a prisoner's dilemma. If you (researcher) defect (publish in Elsevier journals), you perpetuate Elsevier's business, a shitty situation. But it's not as bad as cooperating (not publishing), because there's a chance that everyone else defects and you screw up your career, a really shitty situation. So out of self-interest everyone defects and perpetuates Elsevier's business.