Sending it back for a disc read error that only requires a lens wipe (or a simple gear adjustment if you will) is definitely making it more complicated than it needs to be.
That "simple gear adjustment" is a tedious and time consuming affair. I don't think you understand what it entails. Disassembling your PS2 down to the point where you can access the disc drive's internal components, then testing each different type of disc and making adjustments until they all work isn't some 5 minute easy solution, and it's not a permanent fix either.
I dunno if they make the slim from cheaper parts to require repairs, but my fat PS2 has been dropped on concrete, left on for days at a time, played with no air ventilation, etc. and it never needed repairs.
As far as I know, these disc read errors only occur with the PS2 fat. I'm glad you've never had problems with your PS2, but that doesn't mean that they never have issues.