unions

That’s not surplus labor. Surplus labor is employed people who don’t have things to do. Or unemployed people who are able and want to work, if you’re taking about the market broadly.

And scientists are low paid at the start - and higher paid later, just like doctors and architects and plenty of people who have tremendous lifetime earning potential.

Scientists in academia are hit or miss wage wise, but have a high quality of life. Plenty of private sector scientists make $$$.