Over the past few months, there has been a lot of speculation regarding Ethereum’s mining difficulty. This problem is known as the Difficult Bomb, and it poses a significant threat to the ecosystem.
It is important to understand the problem of the Ethereum difficulty bomb first and foremost. When Ethereum was first created, the developers had to create a consensus algorithm. Similar to Bitcoin, this consensus is achieved through mining in a proof-of-work environment. However, with the mining difficult going up over time, it could potentially create a problematic scenario. After all, it does not appear there will be ASIC-like mining hardware for Ethereum anytime soon.
However, the Ethereum developers have come up with a different plan. From the outset, the plan was to make Ethereum mining impossible at some point in the future. This change will be introduced through an arbitrarily difficult block to mine, which will effectively create the difficulty bomb in question. As this difficulty bomb is activated on the network, the mining difficulty will skyrocket and eventually make Ethereum mining unfeasible and extremely unprofitable.
Source: What is the Ethereum Difficulty Bomb?