Throughout history we have resistance against the introduction of number 0 into numbering system (introduced by the Arab mathematicians in the 9th century AD based on their study on the works of Indian mathematicians).

Then we have resistance against the complex numbers introduction into numbering system (introduced by the Italian mathematicians in the 16th century AD and then made popular by Euler in his famous formula).

And now we have resistance against geometry algebra (GA) in the 21st century AD. I think the main reason Heaviside (the inventor of the modern form of Maxwell's Equations) was opposing the usage of quaternion equations utilizing "versor" is probably due the difficulty of its manual calculations compared to his rather limited "tensor" based proposal. The irony is that Maxwell himself was originally using quaternion based algebra or GA for his discovery of the EM equations. Since now we have very powerful calculators/computers compared to the 19th century AD this should be a non-issue for the practioners.

IMHO, people who work in electromagnetics (EM) have no choice but to adopt and work with GA due to the nature of the EM waves in which (unlike other waves e.g. sound) it has additional polarization property that is cumbersome to manipulate using conventional complex numbers.

Eventually, someone will come up with a better replacement of I/Q data and probably call it IQ2 data where the extra Q represents quaternion.