A $50/hour union wage, with generous pensions and benefits, would make people reproduce like rabbits, and quite 'successfully', too.
This is a function of both money and time. Think of some relatively well paying fields like engineering, accounting, and the skilled trades. It isn't all that hard to make $50/hr eventually and most people can make $25/hr + with decent benefits, yet they aren't running off and having 1920's Catholic families.
That's because those jobs require enormous competition, stress, and decades of study, DQ! The whole point is to give the mass of people $50/hour plus total security as a matter of course. Then they feel confident and can reproduce. Just because a tiny minority of the upper-working class can buy a slightly better job through huge expenditure on endless years of education and high-stress lifestyle doesn't mean they'll reproduce - heck they don't even get out of school till 30, and then they're paying off student loan debt till 45 or so years of age.
Opebo, notice the jobs I chose. Engineer, Accountant, skilled trades. None of these take very long to get one's certificiation and the trades aren't too challenging academically. In my relatively low cost area, you can get a plumbing diploma at 20, and make $50k+ per year before 25. Still, the skilled tradesmen aren't getting their 1950's housewives & 5 kids.
The low birth rates in the west go far deeper than salaries (although that's part of it). There is a much stronger cultural component holding them down.
Accounting...ehhhh...from what I understand, it can be hard but there's one real weeding out class that is generally taken in an Accountant's general course of study. Generally, to become a CPA that gets paid a professional salary, you need a MS in Accounting. In total, that's a bout 6 years of school and you have to take a certification test at the end and even then, the pay is relatively modest (mid 40s for a CPA and high 30s for a regular undergrad in accouting starting out)
Engineering can be a bit more challenging. Generally, you have to take 4 or perhaps 5 or even 6 difficult serious (non-High School) math classes (Three semesters of Calculus, one semester of Differential Equations and perhaps one or two semesters of discrete and linear Algebra) and then you have to take 2 Physics and at least 2 special classes in Applied Physics. Each one of these classes has a fail rate of about 30-40% and generally those committed to this field may have to take at least one of these classes twice unless they are clearly above average in aptitude and on top of that, Engineers generally have like a whole extra semester of hours they must finish to graduate and take a certification test as a condition of graduation. It is not considered underachieving to graduate from Engineering school a year late and with a GPA in the mid 2's (or low 70s) However, they generally get paid in the 60s but only have job security for about 5 or 10 years before they are forced into Management or Research. That requires probably going to Graduate school in Business or Engineering and though most jobs after that are 6-figures, the competition to keep those jobs are stiff as most firms that hire these guys have "up or out" career tracks.
So, there really isn't a career path that's specifically reroduction-friendly. They either have low pay (teachers, accountants) , long hours and high education requirements (doctors, engineers) or very little job security (lawyers, managers).
The only way to be in a good position to multiply is to put out your own shingle and unless you get it right, low pay, long hours and poor income security are your only friends.
