Are Viruses From Venus and Prions From Pluto?

This may just be the ramblings of an old academic who has been in a Covid-19 lockdown since March and has too much time on his hands. I couldn't help musing on the fact that most scientists disqualify viruses (whether DNA or RNA based) and prions (impressively heat-resistant 'rogue' proteins) from the category of 'living things'. This is on the, not unreasonable, basis that they lack certain features of animals, bacteria, fungi and plants, as well as having odd unique features of their own (e.g. you can crystallise a virus). I was minded, however, that parasitic organisms lose any unneeded abilities of their free-living counterparts (a Liver fluke doesn't need to detect light or to swim). So, could viruses and prions be highly simplified parasites?  They are all dependent upon other life forms for their energy sources and their ability to replicate, consequently losing some of the unneeded characteristics of living things. I was also thinking of Bartlett and Wong's formulation of the concept of 'lyth' to help identify alien life forms. They point out that lyth on Mars (or any other extra-terrestrial body) may be analogous but not identical (in terms of chemical composition of its constituents and energy sources used) to life on Earth. They suggest that lyth would have 4 characteristics, namely the abilities to 1) Absorb and change free energy sources; 2) Grow or expand exponentially; 3) Restrict internal change when external changes happen and 4) Record, process and carry out actions based on information. Pretty obviously, it is easier to see items 1 and 2 as clearly applicable to viruses and prions, than 3 and 4. But what if their exploiting a host organism minimises external changes as well as removing the need to change responses based on information? One could also pose a question of what would happen if a virus-like entity was identified of Mars (with reliable evidence that it had not been inadvertently introduced from Earth). Would it be classified as 'lyving' and would it be regarded as evidence that there must have been earlier life for it to parasitise?