ADC popularity is at its lowest in low MMR, where games go the longest. So giving Iron-Silver players a promise of late game power is pretty reasonable. Also, new toys do a good job of bumping play rate. Both 13.1b and 13.10 spiked bot lane pick rate. The same thing happened with jungle in 12.22
For pro play, I'm more concerned with ensuring carry champions are pro-viable in top and mid. If top lane is a lot of Jax vs. Gwen vs. Rumble vs. Renekton, you'd be hard-pressed to call it an "ADC" meta when Gwen can just solo-kill Aphelios like we saw at MSI. Certainly not a fun experience for many ADC players, but also Silver players can't play Gwen, so 🤷♂️.
Finally, pro players play Challenger solo queue and scrims, both of which are incredibly fast-paced and snowbally on average. I'm sure there will be some degree of "Let's just get 4 item Jinx and then we win," which wouldn't be great. But if she has to face up against 4 item Gwen it probably works itself out.