How does being "too busy" affect dating or being in a relationship?

I've heard too often that people are "too busy" to be dating, or be in a relationship.

(I'm going to say my definition of "dating," which is when people are going out and getting to know someone who may be a potential partner, but they're not in a relationship.)

A lot of people are busy, and there are people who have full-time job and kids to raise, and they are maintaining their marriages, not just relationships or dating.

What aspect (s) of being busy affect any of these?

I think I can't understand this because I would've been understanding and wouldn't be needy for attention all the time if I were in a relationship with someone.

Therefore, I have not understood how people think they need to be not busy to be dating or be in a relationship? I need to hear different perspectives to understand.
Updates
4 mo
Rephrase: What aspect (s) of dating or relationship does being busy affect? / How does being busy deter dating or relationship?
Updates
4 mo
And I wonder those who are "too busy" to date or be in serious relationships, when would they be "unbusy" if they maintain the same jobs and same lifestyles?
How does being "too busy" affect dating or being in a relationship?
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