Can't!

Many people say that they can't do this, can't do that.
They can't sell insurance, can't become successful etc...

But have they ever think back since their birth;
they can't walk, but then can walk and even run,
can't talk, then can talk, and even has a debate with each other,
can't write, then can write well, and some even keep publishing books and achieved New York Best Seller Book Awards,
can't wear clothes, then can wear nice clothes and run after fashion styles,
can't ride bikes & drive cars, but now drive good cars, some even have car racing
..........

So many can'ts, but now we can.

So now, can we still able to say that we can't do it now and forever?