First of all, Bitcoin is not fully owned by the top 5 mining pools as you say. BTC isn't owned by anyone and if the mining pools ever decide to change the parameters as they like, we fork off and solve the issue within hours at most.
Then, there wouldn't be just 0.0000001BTC per person. 21M coins divided by 7,800,000,000 people is about 0.00269 per existent person. Bitcoin is way easier to be moved around in much smaller quantities - you can't pay with 0.0000001$, can you?
The global wealth disparity will be a thing no matter how much we change things. There'll always be someone who earns more (or steals from others). We can't really change that unless we apply communist rules.
Okay lets look at your theory: BTC forks off with every miner but the mining pools:
1. You can change btc from sha but then every btc miner now has to get new equipment since they all use asics. Your coin probably dies now
2. You can keep the same algorithm and then a few of the top miners from those pools will regularly attack your coin with their hashing power like with bch. Lets say they are nice and don't attack you. Your coin now cost way less to mine than theirs and so the price will fall, many will see this already as not bitcoin as they usually count the one that is the highest price when forks like abc/sv happened. So still you haven't created a new bitcoin.
How do you avoid these scenarios and take back control from the mining pools?
Also I like your maths but that is actually exactly what I am asking
if you divided all coins evenly then btc could be a global currency, but btc isn't, its held in a pyramid. So i calculated the average amount of btc(i actually did this for other coins too and realized they all share a similar distribution structure however some just havent reached as many levels of the pyramid yet due to a small mcap/users) held at each level and extended the pyramid downwards to ~5 billion users. At the last level will be 1 billion people who have that little amount of btc.
The global wealth disparity doesn't have to be a thing. It's only defeatist propaganda you've been fed that makes you believe so. Similar to how creating a currency not owned by a central bank is not a thing that caught on until bitcoin. People who earn their money are not the issue, one could argue maybe they pay more taxes etc. but thats to be decided. The issue is with people who don't earn their wealth- either through stealing as you say or simply inheriting.
This unearned wealth creates the issue because most people would reward someone for doing good. Almost no one would reward someone for doing nothing or worse hurting others. Yet in most parts of the world the wealth is held by people who were friends with kings, dictators, etc. from the last few centuries. I am not especially into choosing an economic side, I just believe we should develop the best system from the ground up. Rather than using a system biased by history to determine who is the wealthiest.