Victoria games are all about that industry. But to develop your country into an industrial giant, your population must be Qualified to take on the burden of such an undertaking.
Like all Pop attributes, Qualifications follow the Pops as they split, merge, move between buildings, migrate, and die. If you had previously developed a lot of potential Bureaucrats in your country but ran into budgetary problems and had to shut down your schools, over time those Pops who have already developed the Qualifications to become Bureaucrats will die off and not be replaced by newly educated ones.
If your Capitalists in a given state had been underpaying their local discriminated employees to the degree that nobody gained the Qualifications to take over for them, and then some of those Capitalists move away to operate a newly opened Iron Mine in the next state over, rather than promoting some of the local discriminated Laborers to the newly opened jobs they will simply leave the spots open, and the mines underproducing, until some qualified Capitalists move in from elsewhere to take over.
Qualifications are entirely moddable by simply providing the computational factors that should go into determining how the value develops each month. If you want to make a mod to split up the Clergymen Profession into individual variants for each Religion in the game, you could make the Imam Profession dependent on the Pop being Sunni or Shi’ite.
Qualifications intend to signal a player what capacity for employment they have available among any subset of their population. For example, they cannot conquer a state filled with under-educated people they also legally discriminate against and expect to immediately build up a cutting-edge manufacturing- and trade center there.
In summary, Qualifications are the mechanism by which access to education and your stance on discrimination - in addition to many other factors - impact your ability to expand different parts of your society. It is also the mechanism that sorts Pops logically into the economic, and thereby political, niches you carve out as you expand, ensuring your laws and economic conditions inform the social mobility of Pops based on who they are.