The Moat
Be Too Big to Displace or Too Sharp to Bother With.
There are two safe places: the giant nobody can topple and the specialist nobody can be bothered to replace.
Danger lives in the middle. If you're a medium-sized, general middleman, you're big enough to be worth attacking and not specialised enough to be hard to replace. The safe positions are at the two extremes: be so big that displacing you is unthinkable, or be so sharply specialised in a narrow, awkward niche that you're not worth anyone's effort to copy.
Pick your extreme and commit to it. Go for scale and dominate, or go for depth and own a corner so specific that you're the only sane choice in it. The graveyard is full of middlemen who got comfortably medium - big enough to be a target, generic enough to be swapped out.
Win by scale or by sharp specialisation. The comfortable middle gets killed.
This is one of 48 laws from MIDDLEMAN - The 48 Laws of the Money in the Middle. Read it in full to climb the whole building, floor by floor.