While I'm not sure about this buy, Cursor does at least have revenue. WhatsApp was basically running on VC/private money (they had an extremely nominal fee, but I never had to pay it), and was sold to buy its userbase into the Facebook fold. I don't think you can compare that to a business that at least has some decent revenue.
I wish people would stop talking about just revenue. It's mostly meaningless without knowing their expenses.
Also revenue is a signal for product market fit. Is it a great one? Dunno. But for example I'd be hard pressed to sell $1billion of anything, even if I had something everyone wanted.
But I think your point about burn rate is important. How long can they have this attrition on cash before they collapse?
Their main product is part VSCode, which is a market that's almost impossible to make money in, and part reselling already expensive LLM tokens.
You can look at more parameters and judge how well a company could do in the future. For Amazon, you can predict that once they stop growing, they can make a pretty penny.
But with Cursor that doesn't seem likely. Even if they had the talent for training models from scratch, which I don't think they do, and IF inference makes money, which is not clear at all, training models is still a huge money sink.
So, for them getting bought out by xAi which has a base model they can use makes sense. But what does xAi get here? Another endless money pit?