Are there any, at least somewhat credible, unicorns that have appeared over the last 5 years?
Realistically people were making these kinds of points back in 2015, and now a large percentage of the lists of unicorns were from somewhere around 2015. It just takes time for most of these companies to become well-known unicorns. The last five years is always the worst five years, until you wait another five years and in hindsight consider it a golden era.
Edit: although I do think that the couple years of high interest rates will slow the growth of startups from this era, since it has a meaningful impact on how much cash VCs can spend. The AI boom at the tail end of high interest rates will probably cover a bit of that though; OpenAI is the first runaway success but I'm pretty sure it's not going to be the last.