That is good in my opinion. It encourages you to bring in new trials and new people without "risking" to waste loot on them.
Also, if the drops scaled with the amount of people, it would just encourage people to make multiple flex runs filling them out with alts to funnel gear.
Individual loot works well for flex in my opinion.
Note: Inb4 someone says invidiual loot or flexi mode would be good for normal/heroic raiding. Just no.