There have quite a few studies in Korean and in English of the rise of the modern South Korean entertainment industry, with particular emphasis on the now global rise of K-pop.
As with most musical genres, certain features are easily gleaned from a sample of music recognised as trot. Its origins are intertwined with most early 20th-century popular music, and features like duple meter, use of the minor pentatonic scales, and melisma characteristic of pansori also incorporated, but also Western orchestral instrumental style (with occasional use of traditional Korean instruments, as opposed to standard frequent use) and a relatively allegro tempo (compared to traditional Korean music, compared to Korean ballads, and compared to Japanese enka).
Its texts are also related to primarily urban settings with recollections and memories of the rural hometown 고향, which fits the historical context of rapid urbanisation in the 1960-80s. The nostalgia element is a heavy part of the text. It has undergone several "waves" of influences, especially in the incorporation of dance, electronic instruments, and new visual aesthetics.
Judging which of these has been accepted into the "soul" of trot is down to the listeners of tomorrow looking back, in my opinion. From the perspective of the late 2010s, it is still a living genre, but one with considerable influence for the older generation and relatively little for the younger generation.