yes, in 20 years all the top players will be way better than Lebron is now. Jordan would be an average player in today's NBA and Lebron will be average compared to the NBA in 2036-37.
That is the nature of sports. Always progressing, more competitive, better athletes. If you don't believe me look at NBA basketball in the 1950s. Those guys sucked. My local high school team now could beat them. But back then they were the best in the world.
This is why you can only compare to your current era, because the next era will always be way better.