In its present state,
the bitcoin system is controlled by a few major mining
companies
No, it's not. What do you mean by mining companies? Bitmain? Mining pools? They do not control Bitcoin. It really deosn't matter who is confirming transactions as long as that entity does not have 51% of the network. Mining is not controlling.
(it is too costly for individuals)
How?
You can Buy Bitcoin with $1 and you can buy it with $1000. Unless you mean that mining is too costly, but why the hell would you want to mine your own coins? Do you also have your own cows and chickens? Do you refine the gasoline your car burns or help print fiat currency that you later spend?
traded through
a few major platforms (finding other bitcoin users without
a meeting place is difficult),
There's actually a lot of trading platforms. What difference does it make how many big players are out there? The world's supply of diamonds is also controlled by just a few individuals. Does it stop people from buying them?
and held in wallets provided
by various companies
If you don't like it, keep it in your core wallet.