I fail to see your point here. Blocks being full or not is depending on amount of transactions made, not on the fact of miners having to pay for your mining or not.
The only thing that would be a problem could be spam transactions if there would be o fee's ,or am i missing something here ?!
It’s not only farming, for instance the media is also heavily subsidized in Norway…
10 years from now, it’s is not unthinkable that some governments will have a very positive attitude towards bitcoin.
We must remember that all governments consists of people, and some of those people will personally own bitcoin.. Suddenly they might want to support the local mining farm..
10 years from now the mining reward will have dropped to only 3.125 bitcoin per block. At that time, I will not be surprised if some well meaning government wants to subsidize its local mining industry.
I believe this will lead to negative consequences for the network.
Those consequences will be even worse if blocks are not full.
If the blocks are full:
Miners will simply fill up blocks with the transactions that pays the most in fees.
Users are competing for blockspace, and the price is determined by how much the users are willing to pay.
This does not change if a government suddenly starts to subsidize its local mining farms
If blocks are not full:
Miners are competing to offer the lowest price for blockspace. They try to include as many transactions as possible while at the same time excluding those who pays too little.
The price is determined by how little the miners are willing to demand in fees.
If some of the miners suddenly gets a government subsidy, they can afford to offer a lower price for blockspace.
Then there is no longer any reason for users to include a high fee, because a low fee will be accepted anyway. This will in turn effect everyone who is a miner, because the price of blockspace is reduced globally.