Intersample overs are real someone did measure some 90's players they all show the problem . But the "problem" is mostly the broken loudness war masters. But it can show up when going to and from different sample rates or from a lossy to a lossless format , maybe less common practices in the past ?
But the fix cost nothing just sacrifice approximately -3db somewhere in the conversion chain ( it fixes itself if you use a digital volume control or replay gain before the DAC ).
Some good manufacturers like benchmark adress this .
Filter ringing on the other hand does not happen with properly sampled signals it's only an consequence of the test pulse , so here you actually make the products worse by "fixing" this by a leaky slow filter or no filter .
You forget the non problem of "noise" via spdiff and Ethernet and USB