Everything changes over time, even a game as old and steadfast as poker.
The game may have been around in some form or another for centuries, but it has undergone constant change in that time. Even in the past 100 years or so, the evolution has been plain to see. The game has moved from draw and five-card stud played in shadowy back rooms of Texas bars to $10,000 world championship no-limit hold'em events televised by major networks with the accompanying glitz and glamour.
Although it may seem hard to fathom right now, it's a pretty safe bet that in 100 years, poker will look drastically different than it looks today.