Well again, the definition of veganism specifically states “as far as is possible and practicable” (typed before your edit) which is meant to cover cases in which someone is literally unable to maintain a life without animal products. In that case they should aim to reduce their consumption of animal products as much as they can even if it isn’t down to zero. That being said, I don’t think that that situation applies to essentially anyone living in a modern society. There are plenty of vegan options in grocery stores that don’t require any more time to make than you would otherwise spend driving to a fast food restaurant, waiting in line, and then driving back to your original route/home. In fact, I would argue that if I stay home and throw together a vegan meal consisting of things that are able to be quickly heated up/eaten raw that I will be able to finish preparing that meal before my friend who goes out at the same time to buy fast food. And even if you have to spend an extra 3 minutes to make vegan food that is hardly an insurmountable inconvenience. Claiming that a few extra minutes of food preparation is worth more than the lives of all of the animals that you would have to sacrifice in order to avoid that inconvenience isn’t a reasonable take in my opinion.

ETA: additionally, there are tons of meals that you can make with essentially zero prep time. For example, I eat rice based dishes all the time by just throwing some rice and veggies in a rice cooker, turning it on and walking away until it beeps. Sure it takes some time to actually cook, but the actual time that I am required to spend making it is essentially non-existent.