Because Glow, up until recently the decision making process has largely been down to opinion, Hubris, ideology and of course dogma.
The 380 is a fine machine, it does what it was designed to do superbly, it just so happens that the "Wundermanagers" thought they could reinvent the wheel yet again!
In service with EK our clever teams on the upper floors began to realise not so recently that the 380 is not as versatile as the boffins in TLS told them it was, from a profitability standpoint it is a one trick pony, that trick being fill it up and fly it to big, slot constrained hubs. If you remove the big, the slot constrained or the hub out of equation then it becomes a lot more of a challenge to turn a profit, there are some notable exceptions but by and large that's the reality.
We probably need a fleet of 60 or so, but ideology, hubris and dogma will mean there will be almost double that, I just hope by then it hasn't killed the host...because no one else wants them.