That part may be valid, I have been biking for 30 years so I know I am going to get a lot of use out of the gear I purchase. At the level of bikes I have, you never "need" anything but when you upgrade things, you tend to ride more and that's always a good thing.
Example: I have what is likely the best aluminum wheels on the market right now.
Last week I ordered carbon wheels.
Do I need them: no
Will I feel any difference: maybe a little in the stiffness department but they weigh the same as my others so not much difference.
Will I ride more often and harder because I have new wheels: yes
Will my fitness benefit from riding more: yes
So my wheels cost a lot more than most people's bikes but that's what I like to spend money on. It is silly but it's what I do.
Nothing against getting a good bike, just make sure you're going to stick with it and be able to appreciate the difference, if any. You can always upgrade a few years down the road, when you know what you want by your own experiences. I can certainly afford a more expensive bike but to me it makes no difference, I enjoy the ride just fine.