Is it true that the time saved when developing in high-level languages is later wasted for tuning applications performance?

Try to write C++ GUI application for 2 days. You can do this easy with C# and WPF.

But here I talk from my experience

I needed one month in order to set up the Environment for the Iris GUI. Altought it’s now beautiful it was a nightmare setting this thing.

This program is written in C++ and the UI is HTML. The 2 talks with a Javascript binding. Think of it like a mini browser.

It works fast and it’s easy to design from a web developer, but I wasted 1 month to make the technology behind it.

It depends on the project you are working on. For a dictionary app I don’t think you need low level language. One must first learn to appreciate the simpleness of high level languages, before starts to optimize.

I think it’s better to make something then optimize than to optimize and make nothing. With that spirit this was the first version of Iris:

Start small, think big or Smart high-level, think low-level.

P.S.
I write this originally as answer in Quora