Middle managers don't provide direction; they are communication points. As to how effective they can be, it all depends on how the org is structured. If it's a product-centric organization (i.e. P&L rolls up under product and operating costs are charged back to the product org) then it can work pretty well. If it's a functional organization (revenue rolls up through a sales org on a regional basis and is combined with costs at the corporate level) then there's really no amount of management that will make it a good place for developers to work -- under the latter model, finance is running the company and you're a pure cost center. The manager's primary focus will be cost control, not product quality. That's a bad situation to work under.
I agree with your second assessment, but it's more of an issue with the consultoware business model than anything. Most consultoware shops start up thinking they're going to get hockey-stick growth, but it turns out every implementation is super-custom and it ends up as a consulting business. Many companies fail to realize this has happened, and end up operating like a software company when they should be operating like a professional services company with hourly billing. Under a professional services model, if a customer wants a feature, you can quote them a price for developing and implementing it. Tech debt gets dealt with because it becomes a bottleneck for revenue growth when you can't charge clients to add functionality.
For every SV-brand startup, there are dozens of small-time consultoware shops serving their local market. They're the kind of places that have been around for 20 years and still only have 100 employees each. They can't ever seem to grow beyond that size because the one-way communication flow from sales to development keeps them in massive technical debt.