Both
Depending on your business you may have stable customers who just keep going. You can’t neglect these forever, but compared to employees it may be of lesser priority short-term.
If you neglect employees on the other hand, even short-term, bad things will happen short-term or long term. Employees remember when they were neglected and loyalties are hard to build.
There are many reasons people stay in a particular job, good and bad, but those same reasons allow for a lot of "employees neglect".
You have to neglect a lot of employees to an extreme level, for a long time, for it to actually make a significant difference. Mostly, you'll loose a few staff, who'll be replaced by new, keen, eager to please/succeed staff who's enthusiasm effectively mitigates poor management, and who's "tolerance for sh.tty management" counters have been reset to 0.