I think people were initially drawn to Grin's similarities to Bitcoin in that it was a new technology with an anonymous founder. However a few things have contributed to it's current perception of abandonment. First was the launch date. Right in the middle of a bear market where crypto sentiment was low. I think this could have affected investors risk factor and subsequently grin's funding in its tender early days.
Next was the way the monetary policy played out. I guess it was no surprise to anyone that the price would flatten out but 5 years is a long time in crypto, so many lost patience.
Then there was the transaction graph scandal. I still hear people say that mimblewimble has a fundamental flaw and this narrative is still holding.
There is still a loyal following and the mining economy is strong so I think that grin is far from dead. However I believe that some significant changes are needed for it's situation to change, whether that be internally (new developments) or even externally (demand for privacy coins).