Remember when adcs had to build lifesteal to get good sustain?
Nowadays they can just rush triple crit because they have warlords bloodlust (which is broken with rfc) and a support rushing ardent to give them the sustain. I remember when adcs brought bt 3rd or 4th item for sustain. Now I see adcs completely ignoring lifesteal items going for triple crit + lw + ga + boots/another zeal item. Hell I remember when adcs had to rush lifesteal 1st item either with bt or botrk.

because of lifesteal, they rushed it because it gave 100 AD.