Definitely, we would and there are already designs for 51 star, and 52 star American Flags. We don’t personally remember when Hawaii and Alaska became States. As we were just toddler. But by the time we went to school we rarely saw a 48 star flag outside of the history books. Here are a 51 star and a 52 star flags with the 50 Star flag in between them.
At just a glance it is hard spot any difference. So putting on one or two more states would not be a paramount concern in American Flag design. However, it is going to take billions of dollars to replace all the 50 star flags, embroidered patches, and flag emblems and stickers that we have throughout the country.
The good news is that our flags never expire, so the former 50 star flags could be used until we were all able to replace them all. I guess that most of the ones used nowadays would just continue to be used until they worn out, then replaced with the upgraded ones and probably the flag masks too, wink.