its based on time. if you have the time to eat all the protein you require go for it. another factor is price. meats expensive, some protein powders, per serving, compared to cuts of meat can be cheaper.
absorption time is another factor. some whey protein absorb very quickly vs digesting a steak etc.
tons of factors involved. if you can get it all from whole food, thats all good. thats alot of eating though.