Why did Alexander Parkes' Parkesine have limited commercial success after its 1862 display?

It remained relatively unstable, prone to shrinking, cracking, and combusting.

Parkesine, while the first man-made plastic publicly displayed, suffered significantly from inherent instability after its initial shaping. Alexander Parkes discovered that treating cellulose nitrate with camphor yielded a moldable substance, but once cooled, this material lacked durability. The material exhibited several flaws critical for commercial viability: it was prone to shrinking, which distorted its form; it could crack over time or with temperature fluctuation; and, notably, it was prone to combusting. These weaknesses prevented it from achieving widespread industrial adoption, paving the way for John Wesley Hyatt to develop a more reliable successor, Celluloid, which addressed these stability issues through further refinement of the formula.