Miners access to change the code is the same as you and I. Bitcoin is open source and code changes are reviewed by layers and layers of developers and approvers. Take a look here: https://bitcoin.org/en/development#code-review
Not to mention, they literally have $ millions in vested interest in the success of BTC by virtue of setup and mining costs. Such a move, even hypothetically, unless it is justified somehow, will cause loss of faith in the value of BTC and the fall in the value of BTC will make them lose value in mining as they earn these in BTC as well.
Not to mention, they literally have $ millions in vested interest in the success of BTC by virtue of setup and mining costs. Such a move, even hypothetically, unless it is justified somehow, will cause loss of faith in the value of BTC and the fall in the value of BTC will make them lose value in mining as they earn these in BTC as well.