Agree, and normally every IT infrastructure has issues. But as far as I understand, the implementation is Virgin's own based on Sabre's system, and this widget on the right is virgin calculating the final price based on fares/flight provided by Sabre.
My frustration with their IT comes from being an android user, where they don't have a website which renders well on a mobile device, forget about an app.
The widget is simply displaying the data (fare information, taxes etc) in Virgin's format.
So if the pricing is incorrect it's Sabre and if the display is incorrect it's Virgin.
With the rendering this is always a problem and doesn't need constant investment as it's not done once and never touched again. (You are aware you can't book a Qantas flight with an iPad ? on the full site?)
I do agree the Virgin mobile isn't great and for a while you couldn't even move to the next flight, so if doing a return booking you couldn't do it.
As I'm in IT Management and also do engineering work too, I would expect that Virgin IT view is pretty simple. If it works probably then the user is happy, IT is happy and the management too. If things don't work, the user isn't happy, IT isn't happy and the management need to understand the complications ... if you sell something you have to invest correctly so you can sell via multiple platforms.
I'm not a web developer, though the website I would imagine adheres to the necessary standards. Running a Google test (which is pretty basic) does give it a tick
https://search.google.com/test/mobile-friendly ... You have to remember that websites are expected to run and work on varies different web browsers (Internet Explorer, Edge, Chrome, Safari, FireFox etc.) and different devices (PC, Mac, iPad, iPhone, HTC, Samsung etc ) running different operating systems (Windows, Mac, iOS, Android etc) and all it's variants. It's a headache, but at the least it should run correctly on the key platforms in which companies would get the appropriate analytics on this.
To through the normal elephant in the room, the "style guide" Virgin uses would come from it's marketing department and what comes from them can cause issues especially if they want non-standard fonts etc. This would introduce some headaches as well.
What actually annoys me with the Virgin Australia site is a lack of content review, which is a full time job at the least. Also, when a good feature gets removed and replaced by a poor cousin, as an example the "Flight Specials" has been replaced with
Great Value Fares on Flights From Australia | Virgin Australia which is just terrible so I have to use the mobile app.
This isn't a rant, but it just requires a lot of thought and you can hope is that the IT department have a clear plan for improvement and have a good management team to assist with the implementation.