It’s more so a realization that you have agency, choice, but have decided perhaps without much intention or thought, to remain in your status quo.

I don’t think it’s literally about flying. It’s about ignorantly complying to a status quo and how that itself is a decision even if you’ve made it unintentionally.

Again I think the resources it takes to fly being a limitation are not what it’s referring to. A bird just lives its life in an area and never really assesses if a flight to a far off land is possible, if resources would support their journey, or any of that. They just do what all the other birds are doing or of course what their instincts tell them to. We’ve ignored migration and birds that do travel great distances as not a part of this as it’s not a literal statement about flying!