Miners do not even run full nodes themselves for the purpose of mining, which is why the increased difficulty of running a full node does not increase the difficulty or barrier to entry of mining.
I am a miner myself, solo mining is only feasible if you are a huge industrial operation, not exactly contributing to decentralization. P2P mining unfortunately is not good enough both due to the increased complexity and incompatibility with certain ASIC miners, this is reflected in the hashrate. More then seventy percent of the mining power is presently inside of public pools, this is a good thing. Pools promote decentralization compared to the alternatives, pools are like a form of representative democracy for the miners.
So you are mining in a BU mining pool? Which one is that?
Today's way of mining, as a core dev pointed out, is a historical mistake that became popular. If they had advertised p2pool from the beginning, then pooled mining might not look like it is today
In earlier version of bitcoin, every miner is running a full node and use CPU to mine, that is the ideal configuration for a decentralized network, because there is no concentration of hash power
However with the rise of dedicated mining software and hardware, the mining start to concentrate at a handful of large pools, this dramatically increased the degree of centralization, because a few large pool can use miner's hash power to change the network without their awareness (2013 hard fork demonstrated god-like power from pools: BTCGUILD and Slush pool rolled back the fork with their hash power, most of their miners did not even know what happened)
P2Pool is painful to setup and run, but if you think long term wise, the future bitcoin mining should ideally all be done through P2POOL or similar way, thus totally eliminate the risk of large mining pools colluding to threaten the network. More importantly, if every miner need to run a full node, then the miner will be very aware of the impact of all the protocol change, thus become more involved in the protocol related discussion