Reasons to decline being in bridal party?

I would feel really bad turning down being in a BP, but I think one reason would be unreasonable expectations by the bride. For example, one of my besties is getting married a plane ride away in an expensive city. I will spend probably around 1500 to get me and my husband there, and shes already talking about wanting me to fly up to go wedding dress shopping, and attend her engagement party (another flight), and destination bachelorette (another expensive flight). While people say you just have to show up, that would not be "reasonable expectations" for this bride. I am thinking I will tell her we can attend the wedding and one other OOT event, if thats not reasonable I understand she may want to pick someone local and I am happy being a guest.

I've had friends who recently had children be upset about being a bridesmaid. There were a lot of events the bride did not make kid friendly and she was upset to leave her newborn home so many times.

Time and money would be my big two. I also don't want to plan any parties or showers. That's at the top of my least favorite things to do. As long as there is someone else that I know would pick up that part of it, I would not really have a problem with it and would make it work. But truth be told, I only have a couple of friends I would think might even consider me. If it was someone outside of them, I'd have to decline.

FH has been in several weddings this year and they've all required travel via bus or plane, hotels for multiple days, expensive suits/shoes, time away from school/work....it's just a lot. Plus we end up spending a ton on food and drink during our travels (not at the wedding of course)

A lot of people seem to be mentioning travel costs. How is that different than attending as a regular guest? Assuming you are close enough that the couple asked you to be in the wedding party, you were probably planning to go anyway. I could see declining attending as a whole, but if you're still planning to go, you really only save the cost of the dress.

$$$ is the biggest reason for me.