The scalability trilemma states that a blockchain can only have two out the following three properties: decentralization, scalability, and security.
Layer 2 protocols aim to make Ethereum more scalable by not always interacting with the root chain. What are the potential drawbacks of layer 2 solutions? It seems to me that by not creating transactions on the root chain you sacrifice auditability, which might be critical for some applications.
most epic drawback is : data unavailability on layer 1(main chain on ethereum) which leads to another epic drawback which is being unsecure of funds located on child chain
What are the potential drawbacks of layer 2 solutions?
Layer twos really do not solve any fundamental problems. Instead, they are a duct-tape solution on the existing Ethereumn L1. There is no other reason, besides the stickiness and network effects of Ethereum L1 ecosystem, which would prefer L2s over better L1s. L2s just give the existing L1 tokens a a bit better place to live with more secure bridge and do not offer anything what better L1 does not.
A price paid for scalability is another drawback. Since L2 need to store data on L1 it is still expensive to use it comparing to other scaling solutions such as sidechains connected by bridges to L1 (BSC, Polygon, Fantom, xDai, and others). Meanwhile, those sidechains can drastically decrease price of L2 settlement by running L2s connected to sidechains.
