Why do women think that 6 months is the recommended amount of time for breastfeeding and then stop?

it is recommended to EXCLUSIVELY breastfeed for the first 6 months, but I feel like so many women confuse this with thinking that it's only recommended to breastfeed for 6 months and then stop and switch to formula even though breastfeeding is recommended for 2-4 years or longer if mom and baby wish to continue doing it . Do you feel like this is a common misconception about breastfeeding? I don't mean that if a circumstance comes up where they choose to no longer breastfeed or something happens where they can't, I mean just the actual knowledge that breastfeeding is recommended for a much longer period of time then the 6 months so many moms claim. I was having a conversation with my MIL and she said "I breastfed for the recommended 6 months", and I said "they actually recommend 2-4 years" and my FIL and her seemed all weirded out by that like "oh that's kind of weird". And I was like "I don't think it's weird, it's very common globally for women to breastfeed for a longer period of time, it is just a taboo subject in America". Do you feel people have a misunderstanding of the duration women used to breastfeed or how women globally breastfeed. I personally think that doctors should inform more mothers about it, I feel like it isn't talked about enough

Edit: by no means was I saying that it isn't a mothers choice. I completely support mothers who choose to formula feed no matter what stage they choose to do so. The point of my post was to point out that many women seem to be misinformed that the actual recommended duration of breastfeeding is longer than 6 months and many women stop at this point because they no longer believe it is recommended to do it. There is nothing wrong with formula feeding. I think you all completely misunderstood my post. The aap recommends exclusive breastfeeding for the first 6 months and then adding solids, ect. While continuing to breastfeed for 2-4 years. There is nothing wrong with choosing formula I was merely pointing out that many mothers who choose to breastfeed often cut it shorter because there is not enough information presented to them that the benefits and the recommended duration of breastfeeding is a much longer period of time than the 6 months of exclusively doing it. Once again of course it's a mothers choice what she chooses to do however I think that she should atleast be given all of the facts and information about her choice that that she has the ability to pick what she feels is best for her and her family