Possibly, though unlikely to be the sole cause in this case; certainly no more so than mtbs I'd have thought, at least not in the summer months when that trail is typically hard packed. The CX bikes are definitely harder on the Yarra Trails during the wetter periods though. Either way I agree that everyone's a contributor in one way or another. By-in-large mtbs move along that section of Fwy trail at a higher speed than a CX bike & going by the widths of the troughs where peoples wheels have dropped it suggests the more recent victims/culprits have been mtbers.
My initial thoughts were that I hoped there wasn't a direct correlation in mentality between these obvious moments of people riding outside & beyond their ability/the trail condition & the knuckleheads/Stravaholes behind the BS straight-line hack work a little further along on the short 150-200m section between Belford Rd & the pedestrian/cyclist tunnel under the freeway, next to Willsmere Park i.e. the "I shit, I Strava; therefore I am" kind of rider.
That whole length of trail between the Chandler & Belford Rd has been largely unchanged & enjoyed by all (spare the aforementioned hackish ingrates) since inception way back when, & while thin, fast & varied in camber it's largely held up well proportionate to its use vs the amount of maintenance it gets, but over the last 12-18mths, with a particular focus on the last few months, things have started to get a bit checkered.