Very good observation. History does afford us with examples of this.
For instance, would Napoleone Buonaparte be remembered today without the Revolution? He was a relatively junior artillery officer of minor nobility at that, with little or no prospects of advancement to the higher ranks.
Even if Europe went to war again during his lifetime, with all of those senior officers of the Ancien Regime on the army list, can we safely presume that Napoleon would have achieved such rapid advancement? He may have shown up in the history books as a footnote if he had remained associated with the Corsican independence movement and been caught and executed. Or else, if he took service with the Turkish Empire, then no matter how successful he became as a general there, who would remember him unless he served against Austria et al and then perhaps he would only be recalled under his adopted Turkish name?
Same for Arthur Wellesley. Would he have only been noticed in biographies of his brilliant elder brother or in the genealogies of the Earls of Mornington? Even if he had been successful as a general in India, how many know of the generals who successful fought there over the years? His seniority would not have given him a chief command in a short war, even if Castlereagh backed him. So a paragraph or two in Fortescue at best?
Hiram Ulysses Grant [aka Ulysses Simpson] is probably one of the best examples of your observation. Without the War for Southern Independence 1861-1865, he would have more than likely ended his days as a clerk in his brothers' store. Not even certain that he would have made the pages in a history of the Mexican War. At best, he would be noted in any work on the graduates of West Point as a failed officer, a failed farmer, a failed businessman and a heavy drinker of the class of 1843. Who knew....?