Let me give you a perspective on this. I moved to the US from India when I was about 17 and I am almost 33 now. My accent has definitely evolved over the years

Let me give you a perspective on this. I moved to the US from India when I was about 17 and I am almost 33 now. My accent has definitely evolved over the years and it sounds a little more American-ish even though I can never be a native speaker. I actually prefer that people can understand me when I talk to them. If someone thinks that I sound American-ish, good for me because they will feel comfortable striking a conversation with me. If someone thinks that I am faking it, they can choose whether they want to interact with me or not and I respect that. So the point is that accents can evolve naturally over a period if the person makes an attempt. Yes it gets harder as you get older. Just because someone sounds American-ish doesn't mean that they are not speaking it naturally. A lot of people do not realize that their accent can actually be a hindrance in communication. They might have near perfect grammar but accents do cause a problem. I know this is a controversial topic and even pg got some flak for saying this but a "neutralized" (notice the American spelling) accent is important for communication. If you are a leader/CEO, even more important.