Yes, I can vote with my wallet, but no, it doesn't make a difference. I've been voting with my wallet since day 1 by never buying an iPhone because of how closed it is, and unsurprisingly, this has done absolutely nothing to change how open the iPhone is.
If you did that then you probably made clear your reasons which probably created mindshare with others which probably has helped the EU open up the iPhone. Don’t be so defeatist because the outcome isn’t immediately apparent.
Voting with your wallet doesn’t mean you get to take away from others. It means choosing companies you want to support.