Because you don’t learn how to code at school. You learn how to code by writing programs in it. Most companies don’t care if you have a nice paper saying that you studied programming at college: people care that you can show that your coding skills are good, and that you love to code.
Fundamentally the most important part of blockchains is not algorithms, nor cloud servers, nor user interfaces — it’s people. More specifically: it’s about accountability between people. This is a concept which is closely related to trust, yet narrower because trust comes in so many forms. For example, trust in a marriage is something that typically is not built on accountability — your wife, husband, or partner doesn’t expect you to file precise reports of everything you did during an average day. Hence marital trust is not something that seems very amenable to a blockchain-based solution, or a technology solution in general. (Of course, if you think you have a viable project concept here, disregard this example and go for it! The market would certainly be enormous.)