I think you overestimate how much you are making and how easy it is to turn money into more money. I’ll take your example and use finance for instance, because that’s what I know.
You graduate at 30 and join JPM/MS/GS as an IB associate. You are making 125k base and 225k or so all in in NYC. You take home roughly 140k of that 225k and you have a family so outside of the 401k you aren’t saving much betwen the 4500 a month you are paying for a 2bdrm and your living costs. You happen to be very good so you make VP between 2-4 years later. Now your base isn’t much higher then before, probably around 250k, but you have potential to make up to 100% in bonus (also the possibility of making much less then 100%, depending on climate/group/bank). So lets say you average another 400k over the next 3-5 years with a take home pay of 225k. Again, you are getting a little more space, taking a little more vacation, etc so you aren’t saving tons. But again, you are at the top of your class so you make MD relatively young.
You are now a 37-38 year old Managing Director making $400k base but roughly $800k-1MM a year all in comp and up to this point you’ve made roughly 1.5M-2M over those 7-8 years. Of that 1.5M-2M you’ve taken home roughly 55% of that between income taxes and now the property taxes you pay on your $1MM mortgage (not a big place in NY area). You have that down payment which ate into your savings and so your net worth now consists of a $1MM house, a couple cars, and maybe $300k in a 401k (so 1-1.5M by 38). There is no way you are compounding that into $10MM.
But you are now making $1MM a year (which is unlikely, but you were good) and you have an unusually long shelf life because you are so good and are able to stick around as an MD for 20 years until you are 58 (unlikely). You have some good and bad years market wise, you get some more responsibility and head up a vertical group, and so you made roughly $1.3M a year on average over that 20 years. You take home on average $700k during that time. You have two kids private school tuition as youngsters (because no one sends their kids to public school in NYC), then college, that comes out to roughly $100K per year in tuiton over say, 12 of those years. Add child rearing expenses, cars for them, a nicer house, vacations, new suits to play the part, etc. With all that you probably are able to save on average $200-300k a year on that $700k.
You’ve now saved roughly $13M on a starting balance of $300k, 20 periods, 8% interest (optimistic), and $250k a year added into that savings. You have a couple mortgages and some cars that bring your net worth up to say ~17M. And this is the best case scenario meaning you are a rock star, which is unlikely. Obviously you can nitpick some of the expenditures, but this is the normal life of a NYC banker. I guess you could try and catch on doing something else at 58, but unless you were a top rainmaker, you aren’t just going to walk into another bank or the C suite of a f500. So maybe you do something else in advisory role but it doesn’t cover your expenses. Your net worth continues to grow but you do dip into your savings regularly enough that it doesn’t grow a lot. You die in 20-30 years with maybe 25-30MM net worth, probably sooner though because of the years banking took off your life.
In any case, I’ve laid out the extremely optimistic scenario and in the highest paying “traditional path” and you are still looking at 10-20MM net worth by retirement. The vast majority of bankers burn out or don’t move up and very few in consulting or other areas get there either. I don’t really see a path to $100M unless you are an entrepreneur or somehow become a top executive at someplace like Goldman and are able to stick around well into your old age (you won’t be able to with just banker responsibilities). But if you are planning on becoming the head of global M&A at MS, you might want a new plan.