It really depends on the size of the company you are seeking for. I have worked in start-ups and one of the largest financial institution.
For start-ups:
As long as you are good, you will have a say in most of the area you mentioned (maybe not policy and long term objectives)
For sizeable company:
How projects are done - as development manager, you will be one of the many stakeholder in the project. Instead of thinking you will be dictating how a project is done, your role will more likely in leading some sort of committee where decisions are agreed upon by all the stakeholders.
Technical choices - the architecture team is responsible for deciding on the technology choices.
Policy - policy change is usually driven by internal, external audit. You will be assigned to take care of the aftermath of the audits depending on your area of expertise.
Technical design - manager usually don't have the technical know-how on the technical design
Long term objectives - these are coming from the investor level by setting ROI target for CEO to meet. It will subsequently trickle down to every level in the organization.
It sounds like you have a romantic notion of what a managerial role entails. In this day and age, management are usually the ones getting slashed. The smarter ones usually stay in senior technical roles because the compensation in the managerial role doesn't justify the risk and the time involved.
For me it's around $1600-$1800/month
https://itunes.apple.com/us/artist/cobbysoft-media-inc./id40...
A portfolio of paid apps. Most of them were created to scratch my own itches. I was learning saxophone at the time and couldn't really find a fingering chart software that can play the exact notes and vice versa. One thing lead to another, that's how it all began.
http://www.optimalplugins.com/
Branching out to wordpress plugins. Speaking of which, I think the headline generator is a really awesome plugin for any blogger. Just need some help to scale the marketing part.
http://www.stickynotespro.com/
A tiny SaaS working in progress :). My mind is always coming up with ideas and I usually write them down in sticky notes or in the note app. However, being a visual person, I need to see the post it to make things happen. If some one cover the sticky notes with a blanket, the task will never get done. Creating this site to store big ideas digitally and have the ability to see all the sticky notes on demand.