They won't because it works in both party's favor. Think Strom Thurmond.
In the meantime we have never had an Admiral remain in charge of a ship who had right sided hemiparesis and expressive aphasia. Somehow the government is able to deal with Admirals whose health has failed. Perhaps we can now start to work on Senators and Representatives who are unable to fulfill their duties.
The Constitution does not cover admirals. It does cover senators.
Hey, here's an interesting thought exercise:
Johnson remains incapable of communication. His wife, with power of atty to make medical decisions, resigns the Senate on his behalf. Legal or not?