Some good points, some bad points.

Re: studying business, yes, a lot of is useless. You get two very good things out of it, and mostly only these two things:

1. You get an overview of all the language, terms, and general domains of business. You'll know most of the common business law clauses, the fundamentals of accounting, basic economics, business models, different management structures (who reports to who, centralized/decentralized, etc).

This stuff actually isn't super actionable, but it makes you know what you don't know. So when an organization is having a hard time redoing their product portfolio, R&D, or your company hits the wall after hiring a bunch of people, you probably react a little bit faster and find some opinions on it a little bit faster. The accounting and business law, by far, are the most valuable things you get. (Project management and operations - scheduling, utilization, re-estimating based on how far you're late right now, etc - are good too. Finance is also good in theory, but can be learned adequately from good books without instruction)

2. Case studies. Almost anyone that studies business will tell you that the case studies are the best part of it. So you'll do a few case studies on crises, which helps you keep things together. Some of the seemingly obvious solutions aren't obvious in a crisis. So you'll look at how Lou Gerstner turned around IBM and the hurdles he had to face, how Tylenol dealt with the tampering thing intelligently, how Bridgestone/Firestone didn't, why DHL couldn't break into America successfully, etc. Many of these are super obvious in retrospect, but actually walking through an executive's psychology during a crisis helps you deal with it later when you have a crisis.

Beyond that - sure, study philosophy. Philosophy is good too. Studying business is no substitute for doing business - it primarily gives you an overview of the important domains, and immersion in a bunch of case studies. If you don't go out and apply it, this is pretty much useless. A lot of it isn't actionable without diving in. None of it is required for succeeding at business.

But there is some value there beyond "outside of the box thinking" - a good instructor on management might walk through the classical innovator's dilemma where a business has high overhead supporting a large market that's going to be cannibalized by an upcoming product. You'll look at a bunch of companies that failed and died trying to transition, and a few that succeeded. It doesn't guarantee success by any stretch, but gives you better chances.

Also, final thought - studying management/business is currently more geared towards runnning a large, mature operation and less on entrepreneurship and creativity and starting from scratch. That's starting to change a tiny little bit, but you need to be very critical picking and choosing what to apply from management studies if you're in a young company - the lack of structure and ability to function in a loose and crazy environment is what makes startups able to move fast and win. Trying to impose management theories broadly is like taking a sledgehammer to that - though, there's tons of useful points from hiring, business law, finding a business model and market fit, marketing, and especially accounting and not having your expenses/cashflow get out of control are valuable. The art and talent is figuring out where more structure produces gains larger than the slowing-down effect they have on you.