There will be a real estate system, but I'd rather have players focus on building and collaborating. Player interaction is important.
There will be prebuilt buildings like I said that a CEO can purchase and turn into a shop. Once they have enough money they can erect their own building by hiring an architect. People can hop job to job as well if they like.
What if you introduced a real estate license or builder's permit people could buy? I don't think people should have to jump between jobs just to build a house. I real life, if people who want to build a house of their typically do not just quit their job for a couple of months.
Hell, why not replace more of the occupations with licenses or permits? Again taking real life as an brown townogue, it's not uncommon for people to have another business on the side (e.g. investing in real estate or selling homemade goods online). While it makes sense for people to have to train to become doctor and policemen, it doesn't make as much sense to make "entrepreneur" (for instance) a exclusive job, or to relegate innovative play styles to a "free-will" job.
Let people buy licenses/permits for selling firearms and items, building, lumber-jacking, mining. Perhaps make different levels of license to replace different job tiers (e.g. shopkeeper vs. entrepreneur). This could be a subset of training. Or you could put limitations on permits/license (e.g. a building permit only allows you to build on one lot, or a license to sell items expires if you don't renew it).
I think your mindset is still too much grounded in the traditional CRPG model. In general, I suggest trying not to make everything revolve around a player's job type. One of the main reasons drugs took off in CRPG so much is because they introduced non-static gameplay that diverged from the job-centric CRPG model.