In a word, yes.
Not that your old bike has anything wrong with it, but a new bike brings with it a whole new set of possibilities and excitement.
On a new bike, the parts alone can make you better by just working better than what you had. That frees your mind up to focus on your ride, your skills, and what’s ahead of you. When stuff works, riding is simply more fun.
The new parts and other components such as new tires make a great team. Fresh parts, usually upgrades to what you had, can boost your confidence by encouraging you to push the edges of your skill set. Pick a little different line, lean the bike over a little harder, your new sled can handle it.
Updated geometry makes a difference. In the past 15 years head angles have gotten slacker, making descending much more confidence inspiring, easier and more fun. Steeper seat angles make riding slacker bikes uphill easier by putting you more “on top” of your bike as the terrain gets steeper. The tires get more purchase in the dirt and the suspension sucks up the bigger obstacles allowing the rider smoother uphill travel.
On the subject of travel, a little more suspension can be better. Along with geometry changes, kinematics (how efficiently the bike uses its travel) have become much more friendly towards uphill travel on bikes in longer travel categories making them better suited to a wider variety of terrain. If you’re a racer, a little more travel may still be the call. XC courses at the World Cup level are getting more gnarly and that trend will undoubtedly trickle down. Smooth is fast, and faster is better, right?
All the aforementioned adds up to a desire to ride more, and when you ride more you get better. If you’ve been thinking about a new bike, now you might have one more reason.