Thanks for filling in the details. I think you just need to conserve. Your well only has a 4 GPM recovery. A couple of high flow showers in a row and you have used up your reserve in the well. It sounds like you just pumped the well dry, and had to wait for it to recover. You might consider going to a cistern or storage tank with a booster pump to the house. This way you can fill the storage tank at 4 GPM for as long as it takes, then you will have 1,000 or so gallons stored that you can use at 10 GPM for a couple of hours.
Instead of replacing the well pump, I would use it to fill the cistern tank, and put the money into storage and the booster pump. You can use a jet pump or a submersible in the storage tank to boost to the house.