Arduino for commercial projects

Hello friends good night, let me introduce myself:
Working with electronic, maintenance since 1995 and never took a programming language to study the background because I was wrong assembly with the first 2 hours and gave up. :slight_smile: This attempt and frustration has about 7 years old.

I have a company to 10 years, and commercialize very simple electronics that paid engineer who developed the firmware in C.
Recently discovered, or rather came to the conclusion that any technical knowledge with programming, or newly formed engineer can do the designs of these products because they are simple, keyboard configuration, display 16x2, arm relay, read presence sensor, serial communication RS232 or USB.

Taking into account my great interest in learning to program micro, do the “thing” in my own way, today I doing the offices of my products, I design to the PCI, polycarbonate panel, etc.

Then I met the “Arduino” in December 2014, a friend showed me a plaque explained some things and fell in love.

I have some doubts, basic, pre learning and would like your help.
For if the Arduino is so easy and is there in the market, I’m going to study and invest time in C?

1 Can I develop product designs using the Arduino, and commercially sell these products?
Obs .: I will not use the Arduino board uno328 or mega2560, I will use only one or mega for learning and development of the product, then I will draw the PCI as is necessary for the product in question, and just burn the firmware that was made upon one, I drew on the board.
Can I create product this way?

2 is reliable create commercial product made with Arduino?
Obs .: I’m having this doubt, as many already said it is not confident that the very problem, others already said it is the language of the future easier, anyone can create projects.

3 Arduino is for the C language as well as Delphi is to Pascal?
This right that statement? Arduino is just a development platform, a tool of C ??

4 IDE (development interface) Arduino is really reliable? Reinforcing the item 1 and 2, I can study, learn, develop small commercial products, and market without headache, which have to give problem will be with hardware because I had to give it !!! I am sure this statement?

Sorry to have written a large text and thank you to anyone who can help me.

grateful;
RodBeo …

Rodbeo, Some of your questions have not been translated well. What is your native language? There is probably a part of this forum where you can ask questions and get replies in your native language, making it easier for you to communicate.