This is true!

What I have learned is only to plan for the next order of magnitude from a sensible starting point. If you are creating a new e.g. AirBnB, you will need a minimim viable performance, let's say 1000 users at a time on the site. After that, you plan for 10000, then 100000 etc. You might get multiple orders of magnitude from the same improvements or changes but you only need to get one more step.

Why? Your team and expertise will be different in 3 years. You might get bought-out or a new thing might come along that suits your model really well. Eventually, you might have enough money to have an entire data centre with 100 support staff but you certainly can't plan for that on day one.