As the younger generations stop rolling their eyes at 'old people' and become 'old people' themselves, I think the problem will be corrected. Requiring smart phone apps is discriminatory, unsuitable for for many people due to an array of disabilities. Some of which, like worsening eyesight, will happen to all of us given time.

Supporting these people are one reason why we won't get beyond SMS based two factor authentication for the foreseeable future.