In 1839 John William Donaldson demonstrated that alphabet groups letters on the basis of their phonetic and articulatory features:

The way he transliterates ו ח ט is not necessarily accurate, but in this context it doesn't matter much,
he also shies away from adding the line of what he calls liquids, not daring to mess around with the order, which is funny, since he continues: "these sixteen letters constituted the original Greek alphabet", which he probably took from Tacitus: "sedecim litterarum formas"

In 1883 Isaac Taylor collects different explanations of the alphabetic order, in which he mentions Donaldson's and doesn't shy away from adding the line of liquids to the table, not shying from moving m to other labials and switching r and k to show that the structure is basically there, and it takes only few modification to make it perfect:

Here he simply transliterated the previous letters. His take on sibilants is not clear to me. In the context of "sedecim litterarum formas" it would be more natural to consider ט "continuous" and drop the others, especially because θ is. And since he started moving "liquids" around, it would make more sense to place L within "dentals" and to place ŋ within the column of "palatals", which few later and much less impressive authors call gutturals, and I would rather call velars.

What I am bringing here to the table is an explanation of why this structure is now distorted:
There is another structure on the top of this one and it's truly shocking how it seems to have never been mentioned in literature, especially considering how spectacular it is in the latin alphabet used by most of humanity: it places L to the leftmost corner of it and R to the rightmost one. And that feature of it could be the reason why the distortion in the previous structure is the strongest among the sonors (previously called liquids)
And because both structures can be seen even in the most ancient abecedary found up to date, naturally it raises questions to which I'm not exactly ready to give a satisfying answer. Since M is misplaced in all the alphabets I came across, probably the author of the alphabet modified it before it could spread, the way it took Mashtots only three years before he added additional letters within armenian alphabet which made these structures in it virtually non-existant. In others though...


What this structure already helps with (other then it may facilitate the process of acquiring alphabets to those who have to learn them early in life or at mastering some foreign language) is that it demands reconsideration of how we transliterate some ugaritic letters, especially in the context of KTU 5.14:




References:

Donaldson, John William. 1839. The New Cratylus; or, Contributions Towards a More Accurate Knowledge of the Greek Language. Cambridge: J. and J. J. Deighton; London: John W. Parker.

Tacitus. Annales. Book 11, Chapter 14.

Taylor, Isaac. 1883. The Alphabet: An Account of the Origin and Development of Letters. 2 vols. London: Kegan Paul, Trench & Co.

Virolleaud, Charles. 1957. Le Palais Royal d'Ugarit II: Textes en cunéiformes alphabétiques des archives est, ouest et centrales. Paris: Imprimerie Nationale; Librairie C. Klincksieck. (Mission de Ras Shamra, vol. 7).