I'm sure Quora views took a hit after ChatGPT. Not like Quora was any good before ChatGPT, they just managed to get to the top of Google results for a lot of common questions.
Now, Poe by Quora was trying to go big on custom agents. The GPT Agents announcement on DevDay was a fundamental threat to Poe in many ways.
I'm convinced that Adam D'Angelo probably had some influence on the other two board members too. He should've left the board of OpenAI the moment OpenAI and his own company were competing in the same space.
If you look at Poe as a value add for existing Quora users, instead of a feature that is going to grow their userbase, it's still a net win for Quora even if GPT agents exist simultaneously.
Poe is not really meant as a value addition for Quora users. Poe was a general AI chat company, like ChatGPT.
Poe's unique selling point was their 'chat agents with customizable instructions/personality' and they were charging people money for this while pretty much building on OpenAI GPT API. They also had an agents store.
During DevDay when Sam announced GPTAgents and store, that was a fundamental threat to Poes existance.