[vasilvv]

Generally, L2 networks are engineered with the assumption that they will carry TCP, and TCP performs really poorly with high loss rates (depends on the specific congestion control used, but the boundary can be anywhere between 1% and 25%), so they try to make sure on L2 level that losses are minimal. There are some scenarios in which a network can be engineered around high loss rates (e.g. some data center networks), but those don't use TCP, at least with traditional loss recovery.

Error correction codes on L4 level are generally only useful for very low latency situations, since if you can wait for one RTT, you can just have the original sender retransmit the exact packets that got lost, which is inherently more efficient than any ECC.