Is it rude not to respond to thanks?

I'm curious, is it considered impolite or disrespectful if someone fails to acknowledge or respond to a genuine expression of gratitude, such as a "thank you"? In today's fast-paced digital age, where communication often takes place through brief messages and social media posts, does the etiquette surrounding gratitude and its acknowledgment still hold true? And if so, what are the potential implications of neglecting to respond to a heartfelt "thanks"?