According to recent data, the size of the Ethereum (ETH) blockchain has grown to roughly 4 TB, and is on track to reach 5 TB by the end of 2020. Notably, in just one year the size of the Ethereum (ETH) blockchain has doubled. This has made it impossible to run a true full Ethereum (ETH) node, which is known as an archive node, on a regular computer, and even if someone had enough TB to download the whole Ethereum (ETH) blockchain it could take 2 years.

The reason that the Ethereum (ETH) blockchain is getting so big so fast is that every decentralized application (dApp) and platform which runs on Ethereum (ETH) generates tons of transactions, and it seems the blockchain data generated by all of the users, dApps, platforms, and programs on Ethereum (ETH) is steadily accelerating.

Indeed, as of September 2019 the Ethereum (ETH) blockchain was only about 200 GB according to the reports of a Twitter user who downloaded the whole thing.

Notably, even when the Ethereum (ETH) blockchain was 200 GB, it took 35 days to download it. Now that it is 4 TB, it would take approximately 2 years to download the entire Ethereum (ETH) blockchain.

It gets worse. With 2-3 TB being added to the Ethereum (ETH) blockchain every year, it would take longer than a year to download one year of Ethereum (ETH) blockchain data, making it impossible to ever catch up and synch an archive node, at least for regular users with regular internet.

That being said, it is still possible to run an Ethereum (ETH) full node, which is much more lightweight since it only records a ledger of verified transactions, unlike archive nodes which store complete snapshots of the Ethereum (ETH) blockchain for every moment Ethereum (ETH) has existed.

It is perhaps a concern that archive nodes are becoming quite centralized in the sense that there are fewer and fewer of them as time goes on due to the blockchain bloat. If one day they disappear, then it will no longer be possible to figure out the balance of an Ethereum (ETH) address at a given point in time in the past. Although this would limit blockchain analytics and forensics for Ethereum (ETH), maybe it could be written off as a privacy feature.