Define "intelligence." No really. I mean it. What is it defined as?
The question of what causes intelligent life to evolve is somewhat stymed by the reality that we have trouble even defining what intelligence means. So that's the real problem here... and an interesting one it is.
If I dig at what is similar among the varied attempts at definitions, I find a common thread: discrete pattern matching. We see it in IQ tests, for example. The ability to identify something in discrete abstract terms, manipulate it in your head, and then draw conclusions seems to be a reasonable basis for exploring intelligence itself.
If I draw from this and my own experience, I find the most critical aspect towards the development of intelligence is the presence of things which do not change over time on their own, but which can be changed by an individual. For example, rocks tend to not move on their own, but a human can pile them up into a cairn. Once piled, they tend not to move (until they eventually tumble down).
The connection between that and intelligence is that I was able to describe these things in language. You can take those words, and manipulate the ideas as you like. If you don't like them, you can knock them down.
There seems to be a symmetry between these environments that have these traits and words within our own languages. I think there's a strong correlation to be argued there.
Some animals seem to have something close. I watch my cat knock a glass off the table. I want to scream at him for intentionally being a pest, but when I look at it, he's as curious about it as anything. He seems generally unsure as to how it will go, even though the little furball has done it a dozen times before. Contrast that with my daughter, who knows full well what happens when the glass gets knocked off the table. There's something different between them, and I would argue that thing is intelligence.
So when it comes to evolution, I would note that while intelligence evolved on Earth, it also didn't evolve millions of times. It isn't clear that it's just the way evolution had to happen. It's much more complicated than that. However, having a species discover ways to intentionally move objects that otherwise don't move on their own, and select for that, is probably a good start.