Objective diagnostics in MS allow for better patient cohorts - lesions, objective measurements of optic neuritis, oligoclonal banding. Even beyond that, they properly split the illness even with 1/10th the patients.
It is a pharmaceutical goldmine for endpoints - but lesion size etc. rarely affects quality of life so it is ultimately irrelevant - it is a spandrel that drives research and massive cash inflow.
Why does CFS get less funding or awareness? It strikes subjects before they can contribute heavily to artistic, career or athletic endeavours OR after they were never going to accomplish them anyways. In other words, virtually no one between 23-27. You would have to be a savant (extremely rare, these people completely disappear into niche academia even when healthy) or have a famous spouse. You will get a few athletes claiming CFS - they are doing it for PED exemptions. You cannot have CFS and be a professional athlete.
MS has its equivalent of the Lightening (?) Process called the Wahl (?) method, something diet-related, and like every illness, has its fair share of attacks from the psychosomatic lobby.
CFS has a mild steak and lobster problem. In the Americas where the myth is that people on benefits eat all this steak and lobster - and sometimes they do it is good tasting. I am in a group for mother's and there is a woman who said "here is a picture of the hike I just did. Anyways, my husband and I are unemployed due to CFS and we are thinking about having our third child it is crazy I know LOL" and then Whitney Dafoe, who is catatonic. I am not too frustrated by this generally (people die from lymphoma, or survive like it never happened, autism has a wide variance) but it is a bad look when a disease has no biomarker or treatments.
MS also has a fundamentally different discourse. So many people are in the field that you can say "Hey, that idea is terrible, you have no idea what you are doing" and they obviously will attempt to counter with a response, but it will not destroy your career instantly. You ever notice how there is no dissent amongst CFS research, and everything can fit somehow within their own hypothetical constructs? You have to be collegial in CFS because 10 people in the world control the money - literally.
MS had CCSVI treatment - it was out and debunked within 2 years - start to finish. That is a treatment trial with patients no less, and a complicated one, with surgeries and massively multi-disciplinary input. In contrast, XMRV was extremely stupid day zero, no CFS researcher said anything other than neutralities and it took adjacent researchers to disprove it.
In summary, MS is more profitable.