The '90's bubble is what the AI "bubble" would be if everyone you spoke to was glowing with excitement about AI, and a few niche analysts were raising concerns about capex.
Instead this "bubble" is packed with people who detest AI and have extremely bearish views on it's future. If this "bubble" does pop, I think it will be the first one in history that every single person saw coming.
Almost every bubble ever had its detractors. Yet they still happened because those who actually had decision power and market shaping power didn't care about any downsides from popping a larger bubble so they just wanted to make money.