Why don't we use the definite article before these examples?

'We need to look closely at business growth, technological advancement, economic trends, and product development.'

I would never say 'the business growth' or 'the technological advancement' etc.

The simple answer is that, if you're talking about a particular instance of business growth, you would use the definite article (e.g., the business growth we've been experiencing).

I think that here we are before a case of uncountable nouns, which don't need the definite article "the". But, not all of the ones you used are uncountable; "trend" is countable, for example, same goes for "development" that can be uncountable and countable.

Considering this, you might use the definite article ("We need to look closely at the product development" is acceptable).
So the difference stays here: you are not referring to a specific development, but rather to "general" elements, the ones you listed.

About countable/uncountable:
The definite article is used with countable nouns, usually. Same usually goes for the indefinite articles:

• The car was parked there. OR I've seen a car.

And not:

• *Car was parked there OR *I've seen car.

You can use the definite article when you are referring to a specific "something" (uncountable) that is been previously referred to.

There is a good explanation here.