Aloe Vaombe died

[Jimc]

I bought 3 Aloe Vaombe 2 years ago here in SoCal and they were fine up until a week ago. All 3 died within a week of each other. 2 were near the house on flat ground and 1 was on a slope 150' away. The 2 near the house was on 1 valve with the 3rd one on a different irrigation valve. They were being watered every 5 days in the summer ( 2 gallons) and as it cooled down a bit every 7 days. The soil after 5 days is nearly dry but not quite. None of these plants had been given any fertilizer since planted. No other issues with other plants on the same irrigation (aloes, agave,cycads,palms).
Any ideas are welcome

[Melt in the Sun]

I'd be looking for mealybugs or something in the crowns.

Also, is the base rotted? Those roots look good...if so, put that thing back in the ground, clean out the top, and wait - it may grow a new head!