This is actually quite false.
Since a (small) part of my day job is reviewing scenery for MSFS, I have to compare bing and google earth imagery often with recent real life photography and video sources in order to gauge the accuracy of what I’m reviewing.
I have found several instances in which Bing was and is more recent than google. It simply depends on the area.
For example, at the time in which I reviewed them, Santiago (Chile), Fukuoka (Japan) and Fort Lauderdale (US) airports had significantly more updated imagery (at times by years) on Bing than on Google.
Adding to that, the latest airport I reviewed (Athens) is blurred on Google, but visible on Bing.
The comparison between Google Earth and Bing Maps is definitely not as one-sided as some make it up to be.
I’ve actually seen a few developers base their research on Google Earth likely assuming it to be updated, unfortunately with rather lackluster results, as their airports ended up releasing outdated already.