I would like to provide a reminder that we mine not only to make short term gains, but also to prevent that the network gets a 51% attack and our bitcoin price goes to zero.
At this point, why would anyone try to do a 51% attack? It would require billions of dollars to get access to miners, which would give someone 51% of the network's mining hash rate. If someone invests billions of dollars into mining rigs, equipment, data centres and personnel, then why would someone attack and destroy a currency with a 2 Trillion dollars market cap? There are lots of billionaires with their own interests in the Bitcoin business, so I don't think anyone will let anyone to do 51% attack.
You should absolutely not mine if it's not profitable, unless you're curious to learn how mining works. It is the design such that once a source of cheap electricity is found, it can be used to reduce profitability of other miners. Such is bitcoin. Altruism makes shitcoins.
I agree with that. If we start mining Bitcoin, it will increase the mining difficulty and many miners will be forced to shut down their miners. Then only rich mining companies will be able to keep their miners on during unprofitability and this will be a huge threat of 51% attack to my mind.