Minimum Fee for transaction

Just thinking about blackrock getting major shares in bitcoin mining companies.

Is there a chance in the future where block subsidies are much lower than today and the hash rate is concentrated in a few large mining companies that blackrock owns we will see a minimum fee for transactions?

To ensure that miners are earning enough to cover the hashrate/electricity costs they will implement a minimum fee so no transactions are included without meeting this rate. This would essentially cut all normal users out of using bitcoin as they could set the fee quite high so only banking institutions who would be handling BTC on behalf of customers would be able to afford the kind of transactions done in bulk.

For any blocks not produced by blackrock owned miners there would be huge competition to get the transaction into the block which would raise the fees for those blocks anyways.

Is there any way of knowing how much of block production is done by these huge mining companies and is this possibility just going to lead to massive competition in mining from all outside groups to compete with blackrock owned miners to prevent this? Or would other miners go along with it because they might be able to earn more in fees because of it?