Is one rewarded for intending Umrah but missing the opportunity due to circumstances beyond their control, and is that considered a shortcoming on their part?

There is no doubt that your effort and desire to perform the rituals will be rewarded. The money you lost, its reward will not go to waste. This is Allah Almighty's decree, so you must submit to His حكم (judgment) and be content with what He has ordained. Seek help from Allah Almighty, and whenever you are able to perform Umrah, hasten to do so. Strive in other good deeds.