Do you know people who have stayed in IB 10+ years? What are they like?

I've worked with a lot of people that stayed for more than ten years, and several of my close friends are getting close to the 10-year mark, and none of them are what you describe from the above. When looking in from the outside, it may seem like those are the only types of people who excel, but in reality, most are regular upper middle-class people.

You are not working 100-hour weeks for all those years, but in order to stay for that long I think there are three traits that most of the people I know share: 

1. Consistent in terms of performance, and being on a slightly higher level compared to their peers. Looking at associate level and above, the difference between top performers and above average performers, is not that great and it can be hard to distinguish for senior people. You don't need to be the absolute best analyst or associate to rise through the ranks, you just need to be above average. 
2. Large networks, either through family or through merit. I've seen MDs who do nothing but source deals, and barely get involved in the execution at all, besides in the absolute final stages. A guy I went to school with was barely scraping by as an analyst, but managed to get to associate, and quickly rose as a star performer. Not the best at making presentations, and not good at modelling, but with strong project management skills. 
3. Lucky on deal staffing or clients exposure. This becomes increasingly important as you advance in your career, because you need to source more deals yourself. If your MD is anything like the above, you will likely have a lot of facetime with senior management. Getting close to Head of M&A in PE-PortCos or CFOs of strategics can offer great opportunities, because, even though your MD owns the relationship to the PE or the main corporate, these people move around quite frequently and might be able to throw you deals in their new roles. I think chance and luck is often overlooked when thinking about successful bankers, and it is not always the hardest worker that excels. The job requires you to be available at ungodly hours, but you're not crushing 100-hour weeks doing "MD stuff", it's just not how the industry works. 

I remember what it was like before I started, but you should not get anxiety for what your career might look like 10 years down the line. I did a Q&A on WSO insta a few years back, and said that I wanted to be a banker for life. Going back, I was very firm on what my career would look like, and I sacrificed my last relationship to a girl that I loved in order to climb the corporate ladder. However, as my career progressed I realized that I wanted to do something different, and after pocketing last year's bonus as a senior associate, I jumped ship to do a CorpDev role for a large American company instead. I've almost cut my salary in half, something which I thought I would never do, and traded it for a better work life balance. I'm still available most of the day, but I leave the office way earlier, and I can work remotely, which I value a lot more post-covid. I guess you could say that I have softened quite a bit over the years.

TLDR; No, there's a lot more normal people in banking than you think, and I would not worry about what your career looks like in 10+ years time.