What's the point of going to a target school?

I’m assuming it has a lot to do with the network and it can also have an impact on PE recruiting

The school you go ultimately doesn't have any bearing on your ability to do the job or how "capable" you are as a candidate. The reason going to a target school is advantageous is because it makes getting in the door significantly easier:

1. Target schools have more robust OCR --> more streamlined access to opportunities. They are actively at your school looking for people. If you go to a school without this, it's going to take a lot more legwork just to get a look. Target schools are an easy way to filter down a huge applicant pool. Ie. People view going to a target school as a positive signal that you're "smart" and "work hard". This isn't to say anything against people at non-target schools, but you're not getting the same "plus" mark for your school. From a recruiting perspective, it's more efficient to go to a school with a large pool of students who have historically been good candidates
2. Larger alumni network in the industry --> easier to make connections and people are net/net more likely to interview candidates that went to their school - especially if they know them personally (from student clubs, referrals, etc.) . Not hard to imagine that if you benefited from an alum pulling for you that you would want to pay it forward as well if you're in a position to recruit
3. More exposure to the industry - At target schools, you're more likely to learn about banking (as an example) because there's a more well-trodden path for students to go into that industry. So to the extent it interests you, you are likely starting earlier in terms of positioning yourself for successful recruiting. This isn't to say that there aren't students at non-target schools who know they want to to IB as a freshman, but there's just overall less exposure and resources. Especially now that recruiting happens so early, that exposure can be a big advantage for those who didn't know anything about the industry before college
4. Being an "excellent candidate" only matters so much. There are tons of people who look great on paper. At the end of the day, there are only so many interview slots. Going to a target school adds an advantage in a competitive process.