Nothing survives forever.
Mountains wear away as the sea spews up new islands. Over the years, the Amiga underwent infrequent, incremental improvement with quality and excitement generated principally by third party hardware and software developers. Advertising fluctuated in between ineffective and non-existent. Finally, with Commodore's collapse, the Amiga was not even manufactured, let alone developed further. It was, more or less, a minor miracle that the Amiga survived at all.