Let me be very clear, stand up pouches can be recycled, end of story. As is the case with most people and trash haulers, stand up pouches, also known as stand bags or stand up bags, are grouped together with other items that are also made of "plastic" and are sent away with the recycle container and together all of these "plastic" bags, grocery store bags, Target bags, plastic clamshells from fruit and vegetables, and of course stand up bags are then ground up and made into "regrind" or filler used for other types of plastics like park benches, signs, parking lot bumpers, etc. Because this "reground" material is of several different types of plastic, it can only be re-purposed for certain types of products, nothing incredibly sophisticated or advanced are made using all "re-ground" plastics.
Stand up bags are made from several layers of film laminated together. Let me be clear again, it is these laminated layers that create the barrier properties so the contents in the stand bag remain fresher for longer. Without layers of barrier film, the product would spoil or turn rotten much faster. If, and the word is "IF" someone had a closed loop system where they could dispose of all of the stand up pouches made from the same, and the word here is the "same" stand up pouch structure, meaning the laminated films would be identical, here you could recycle all of the layers of film and start again and ultimately use this ground up plastic for more advanced applications.
As anyone could imagine, that's difficult to do at this time in our recycling world. Just now recycling methods are being developed, or equipment is being made, to "identify" these different layers of film in various types of plastics so recyclers can actually find and combine "like" plastics so ultimately we'll have different grades of "re-ground" plastic which can be used for higher level applications.