Yes you’re right the major discussions on the forum is mainly about price and that’s because many people into bitcoin are in for the profit side only.
But the two discussions you also brought have been discussed here multiple times.
- The long term security budget: As the block subsidy decreases every four years, minners will eventually rely mostly on transaction fees. This may sound just okay but Now the challenge is if the transaction fee alone will be enough to incentiveze the minners to secure the network?
There is also possibility of hash power declineing and that will make attach cheaper. How do we cob this?
All this are less discussed because they are not really a problem now, but it might be a critical problem in the future based on protocol decisions made today.
This particular discussion is one of the most widely discussed technical questions even on this forum.
This particular question remains unanswered because the period before the block subsidy stops coming is still far from today although in the next few years like 20 years from now block reward will be around 0.048 which is definitely low and since we will know whether we the fees will be enough incentives for the miners and if not something will change because we have seen forks for bitcoin best practices in the recent years.
But for me I think fees will be enough if the market price of bitcoin continues to increase and also the more adoption it gets the more people use it for transactions and therefore more fees most especially if it’s starts to get accept by business then even second layer networks to can come in
- UTXO set growth: the bitcoin node maintains a data of all UTXOs because transactions really rely on it. now with increase in the growth of UTXo set data the memory storage for a node increase, and large node requirements may discourage individual from running full nudes. If people are not running full node great reliance will be on institutional node, and it's reducing decentralization. This should be a concern aslo.
This has actually been a concern and has also been discussed freely here, for some people who don’t have space they can simply try pruning which is run a prune node for space more space.
why I don’t worry much about space is because technology is growing in the past a 1GB data or file was a big one because of lack of storage means but today we have even phones with TB for storage. So I think technically advancement will help solve this one and shouldn’t be a worry at all