The most important assets are people vs are the people
Could you help, please
The most important assets are people vs are the people
Could you help, please
As with most things you apply the definite article to, the difference is specificity. If you say
The most important assets are people
You're just saying that what's important is people in general, but no specific group or subset of them.
The most important assets are the people
Would be referring to the population of a particular place (as per the idiom). It could also be referring to a specific subset of people already referred to, but this is unlikely as usually if we refer to a specific group of people we give them a more specific name, like "the workers", "the French", "the employees" etc.