It's not really a matter of can or can't -- rather it's a matter of choice/preference. With my bio-loads and filtration (and like you, great water right out of the tap), I could go a month without doing water changes, but choose not to as I simply don't think that's best for my fish.
Also over-filtration certainly doesn't replace needed minerals etc. and it's only going to handle the given bio load, any extra is pretty much superficial. And getting back to water changes, or shall we say tank maintenance, unless one is regularly and often cleaning their sumps, HOB's, canisters, sponges etc., all the waste/detritus is just piling up somewhere in the system, which means more nitrates and other pollutants that aren't removed by most filters.
For most people the only way to remove nitrates is water changes --over-filtration won't help much if anything in this regard (unless one has a heavily planted or aquaponic system, or has filtration with true anoxic de-nitrification going on -- very rare in most of our FW systems).
But of course as you imply there will be exceptions/different experiences, I'm only stating the most commonly suggested/used approach, which for most would be closer to weekly than monthly.