1) The top knows what the organization is capable of and can set achievable goals
2) That the bottom is incentivized to do things that achieve the goals of the company
A manager being technical helps #1, information flows upward more accurately.
I think #2 is more nuanced, but when you have a boss, you are directly incentivized to please the boss, not directly incentivized to achieve the goals of the company. Those can be different things and the less technical a manager is, the more different they can be.
This isn't an argument for just promoting individual contributors, though, since lacking management skills also makes both of these problems worse.
It is an argument for flatter organizations. Maybe that's a better way to look at it, every layer of management makes 1) and 2) more difficult. (A fully flat organization wouldn't have either problem at all.) But if a manager has both management and technical skills, it's more of a partial
management layer.
Smaller orgs should be mostly flat. When I see 20 person companies with too many "directors" and "managers", it's a bad sign. Too many bosses, not enough workers.
The smaller the org, the more you want someone that actually understands the work being managed. Maybe your team is getting work done fast, but it's not done right: no documentation, few tests, architectural flaws, performance issues, security problems... Someone should be able to understand the trade off made, and be able to explain them. When one of your engineers gives you an estimate, you need to understand if it's reasonable. Is it too optimistic? Is he blowing smoke up your ass and spending 2 months on a 2 week job? Poor management sets arbitrary deadlines and wonders why they aren't met.
1) The top knows what the organization is capable of and can set achievable goals 2) That the bottom is incentivized to do things that achieve the goals of the company
A manager being technical helps #1, information flows upward more accurately.
I think #2 is more nuanced, but when you have a boss, you are directly incentivized to please the boss, not directly incentivized to achieve the goals of the company. Those can be different things and the less technical a manager is, the more different they can be.
This isn't an argument for just promoting individual contributors, though, since lacking management skills also makes both of these problems worse.
It is an argument for flatter organizations. Maybe that's a better way to look at it, every layer of management makes 1) and 2) more difficult. (A fully flat organization wouldn't have either problem at all.) But if a manager has both management and technical skills, it's more of a partial management layer.