Why Do Reputable Members Leave Active Signature Campaigns?

[Yamane_Keto]

You're asking a very personal question; why didn't you send them a private message instead of creating a thread?
Signature campaigns are a personal choice, and only the campaign manager have the right to ask this question.

[RGBTC]

Though , that campaign ended just one week later.

The duration of a campaign is usually not announced at the outset/can't be determined with certainty; though some managers may indicate that a contract runs for a specific interim period or that funds are secured to cover payments for the coming weeks. Ultimately, the decision to extend or terminate a campaign mid-contract rests with the company. There are no guarantees.