Nice effort, however, I believe this is flawed. The first question to be asked is - who do those fees go to? Companies' P/E ratios are based on the assumption that profits are distributed as dividends to shareholders, who can thus capture this value.

Let's look at Aave now. The 5.81% the borrower pays goes to the lender depositing the ETH the borrower borrows, not the holders of the AAVE token. Hence the token holders don't capture any of this value, unless there is a separate mechanism for doing so.

This mechanism does exist eg in the case of PancakeSwap, where there is a 0.2% swap fee which is used to purchase and burn CAKE, thus increasing the value of CAKE for current holders. This is the real fee you should be using for your calculation.

If a protocol currently doesn't have any such mechanism for transferring the volumes to token holder value, then token holders don't directly benefit from increased volumes and it's meaningless talking about a P/E.

Please let me know if I missed anything.