Thats why it goes up. People think less qualified candidates pass the interview; hence, expect better and quicker answers with good communication skills along with showing the knowledge. It will continue going up and require more study time. Older folks will get screwed if not in management.
The point is that those aren't extreme counterexamples but are relatively common ones. Solving 100 LC can mean very different things and have very different effects based on the person. The focus should definitely be qualitative not quantitative evaluation of one's understanding of DS&A.
So you’ll just leetcode. That’ll work for fang may be but if you’re unlucky then you’ll have hard time explaining OS fundamentals in other companies for instance. So sure be a code monkey but don’t assume that this is all it takes.
There is no magic number, just be able to solve a hard in 30 minutes and explain your process. Only you know how good you are. My advice is do a mock with a friend of recent questions from the discuss section on LC and have them grade you. Do this a bunch of times till you feel ready.
New grads, please don't get the wrong type of ideas with leetcode being the end-all achievement. Someone is making money off books and websites, while the industry, FAANG especially, are fucking up hiring processes. Know your stuff that they teach in school well.