Perplexity doesn't have a model. You are likely benchmarking it against something under the hood of Perplexity and you can adjust to go with GPT-4o, Claude, etc.
Mistral, by design, uses small models and focuses on text. The downside here is that it doesn't keep up with GPT on complex tasks, and it's not good for coding, math, or reasoning. They are coming out with Pixtral but you can already see costs starting to go up with that. Realistically, the clients I have, always get jazzed about Mistral but when you put things in production and benchmark, Mistral tends to underperform.
I do agree with you that US start ups are spending like drunken sailors. Revenue is coming in but the constant need to update and retrain really eats away any revenue that comes in.