TCAS has never been a replacement for see and avoid and was never intended to be. I've never met a pilot who actually thinks that it is. Certainly, any pilot using it regularly soon discovers the limitations of the equipment and knows where to place the information it gives, as far as prioritites are concerned. I consider mine an extra pair of eyes, nothing more.
I wonder if those who say they don't want it at any cost would also object to anyone in the other seat pointing out other aircraft, similarly would they not bother with an ATC radar service because they would object to being advised of other traffic? Both of these also provide assistance to 'see and avoid' but similarly are not infallible.
TCAS I offers basic collision avoidance information to pilots as an aid to ‘see and avoid’. The main difference from TCAS II is that it does not generate 'Resolution Advisory' (RA) warnings. Because of this principle difference, TCAS I systems are less costly and smaller, making them attractive for those operating at low levels and/or outside controlled airspace where extra information to assist with ‘see and avoid’ is most welcome.