You’re telling a business to change their login requirements (big inconvenience for them) so you don’t have to use an app (small inconvenience for you) and if they don’t you’ll quit (big inconvenience for you, small inconvenience for them). That’s almost never going to work.
But the calculation isn't as simple as you suggest. Smartphones save them money over the older system, which used RFID cards. That meant they needed local staff to handle lost cards. Now if you lost your phone, it's all up to you, and they can deal with other issues over the phone or in-app chat.
The older system allowed booking group classes on the app, online and on a computer in the gym. There was an RFID scanner in the group rooms to check in, with a printed receipt to show the instructor.
The new system got rid of the online and local booking options, and the scanner and printer, which saves them money.
If they figure 1% of the members might leave, but they get more profits from the remaining 99%, then they'll just shrugs at you cancelling your membership over it.
That's why we've collectively stopped using fossil fuel, stopped buying clothes made with sweatshop labor (so garment workers in Bangladesh have no need to protest over minimum wage), stopped eating chocolate made with child labor, and stopped buying electronic devices with cobalt from "artisanal miners" in the DRC. /s
https://www.yahoo.com/entertainment/tv/articles/why-people-c...
I think https://en.wikipedia.org/wiki/Suspension_of_Jimmy_Kimmel_Liv... is a better link for the economic impact of the consumer boycott which, after all, was only part of the negative consequences they faced.
That was a year ago. Have you rejoined, or is your boycott permanent?
As regards to the fuller context, a short-term boycott against an ill-conceived decision based on transitory event seem far different than, say, the ineffective consumer boycott against Coors for its anti-LGBTQ policies, or the effective consumer grape boycott combined with the strike against table grape growers in Delano, California, both of which took years.
The systemic issues like the expectation of universal adult smartphone carry, much less the climate ad labor exploitation issues I mentioned, don't seem readily resolvable that way.