"failed to illustrate" is a perfectly correct and usable phrase in written English.
You can use it when you want to describe a situation in which someone did not succeed in providing a clear example or illustration of something. For example, "The presenter's limited knowledge of the subject matter failed to illustrate the concept adequately."
The original correctly showed the party that won each of the 36 constituencies but failed to illustrate that a further 35 seats are allocated from the party lists - giving 71 seats in all.
What the map failed to illustrate was that the abortion rates in many of those European countries were among the lowest in the world, much lower than in many countries where abortion is illegal.
TWD uses violence in the same way that GoT, at its worst, uses sexual assault: as an illustration of generic brutality and darkness, a way to convince audiences that the world in which they've been dropped is often an ugly one, as if the executions and torture and disembowelments of episodes past somehow failed to illustrate that.
Importantly, similarly analyzing total prescription dose failed to illustrate a statistically significant impact.
However, the stratified analysis failed to illustrate important differences in outcome by mould-active antifungal class.
The "Relevance" was inadequate because PAs generally failed to illustrate key points visually or contained visual distractions.
It effortlessly captures the perfect image all novels fail to illustrate in its blending of photo-precision and haunting narration.
Too often, we fail to illustrate our research findings with descriptions of the circumstances of injury.
Most importantly, OFAT technique fails to illustrate the interdependent interaction between two factors.
Typically, the degree of slip is graded according to plain AP and frog lateral radiographic images, but these fail to illustrate the acquired retroversion from SCFE.
