Why worry? The black cable is external grade, and is completely waterproof. The section tacked to the wall is more vulnerable to damage than the length in conduit, even then it's normally good for thirty years plus unless accidentally damaged. My setup is now 26 years old and has no visible damage or ageing on a long length of south facing wall.
If you really feel strongly about it, then you can buy the cable covers used by BT, as fitted next to the VM cable in your pic, and fit them yourself. Might need to bodge the No. 4 connector to fit the VM conduit.
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