I'll wager that the average senior designer has twice the seniority of the average senior QA engineer. In the quality assurance literature, anecdotes report that the most successful quality programs involve every person in the company, while the quality assurance department becomes more a scorekeeper that a line of error defense. I would say that quality, safety and security are everybody's jobs. Your observation appears correct to me. I would rather say that certification is highly desirable.
Necessity is a most difficult concept after one moves beyond the basics of air, water and food.
But the basic issue is to obtain or create some certification agency. My attempt to interest the Society of Professional Engineers met with silence. I conclude that it will take at least one major accident with significant loss of life, this accident attributable to software failure, before there will be sufficient interest to establish a certification program. Much depends on what else is going on in the economy at the same time. This was relatively recent, too.