Ethereum 

Ethereum was the first of many that would try to utilize smart contracs on-chain and tried to position themselves as the Money of blockchain. But the low transaction per second prevents that from happing. In my opinion ETH started to early with their decentralisation, which resulted in slow progress and a number of vital updates that didnt pass the voting.

Their latest upgrade (Shangai) changed their consensus mechanism from PoW to PoS. So no longer the need for expensive energy consuming miners to calculate new blocks and secure the network, this could be considered a win, but it now rewards the people with the highest ETH stake and keeps money flowing into that direction, is that really a win for decentralisation? Not sure tbh

But it is required for the network to grow beyond their PoW capabilities. The blockchain will be expendable by having multiple chains when busy and shrink when it is quiet again, but for that part we are still waiting, at least i have had the experience 2 years ago, so it isnt progressing very fast you could say. Hence the multiple L2 solutions for this project... Show Less