The ACA really isn't as great for insurers as you seem to think. The idea was to force insurers who participate in ACA markets to insure people who are more expensive with lower premiums, then subsidize this by forcing young, healthy people (well known for their vast wealth) to pay for more expensive policies, with subsidies if they are earning less than some amount. However, my understanding is that the subsidies and penalties for remaining uninsured were too weak, and many people found it more affordable to remain uninsured. This leads to severe adverse selection, higher costs for insurers, which leads to more expensive prices, which leads to ACA plans becoming less attractive. More young people leave, and the cost per insured person rises, so overall costs rise. Turns out there's a reason insurance costs more for the old and the sick, and it turns out young people are not interested in spending thousands of dollars to give them insurance.
Long story short, any insurance lobbyist who pushed for the ACA in its current form is likely not an insurance lobbyist any more.