I think so, in fact most of the fees I got was thank to CLBOSS, a software that I highly recommend for "pleb nodes". https://github.com/ZmnSCPxj/clboss

In the beginning I was obtaining less fees doing all the work by myself. I certainly was not as good as CLBOSS at adjusting fees and selecting nodes to open channels to. I can tell you confidently, if I would have started with CLBOSS in the beginning (but it didn't exist yet) with 8 BTC, I could have probably 10x-20x the amount of fees I have earn. So I have earn 400k, it would have been like 4M-8M with 8 BTC. It's around 1% yearly of your liquidity for small nodes, but probably up to 2% for bigger nodes, in my calculations. Add to that that I had a creepy connection, sometimes hours or days without connection, so yes, I could have earn a much higher fees.