The mother of invention

I think that 'Nececity is the mother of invention' means: Needs bive birth to usefull inventions. for example, Alexander Gram Bell figured it was impractical to send a messenger fo all communications, he invened the telephone in order to fill the need. The same goes for the Wright brothers. the need is the ability to travle log distances quickly and the invention is the airplane. There are several other inventors/inventions that i'm not naming, but the story is the same: need - inventor - invention/soluton.