To be fair, part of the reason why more insurers are pulling out of the exchanges is undoubtedly the threat of government subsidies being removed... But Aetna's business model doesn't fit with that type of plan anyway. They're more in the premium-level market. They always did lose money on those programs. Some insurers optimized for lower-level markets seem to be doing quite well with ACA-subsidized plans. At least as long as the subsidies hold up.