Warner, who has played 101 tests and more than 200 limited-overs internationals for Australia, said he had tried to impress upon younger teammates, including Sydney Thunder talent Oliver Davies, the importance of the longest format.
"I was speaking to (Davies) the other day. He likes playing white-ball cricket, I can't see him playing red-ball cricket any time soon," Warner told reporters.
"If he wants to put his mind to it, he can definitely play.
"But I've got a little bit of scaredness about what's going to happen in the next five to 10 years, where cricket is actually heading.
"I'd love for guys coming through to play red-ball cricket and play test cricket because that's the legacy that you should want to leave behind."
A number of top Australian cricketers have carved out lucrative careers on the global T20 circuit without playing tests, including Tim David, Chris Lynn and Marcus Stoinis.
Warner suggested they were the exception and that most players would be better off boosting their value in test cricket.
"There's only been a small minority of people who have been able to do that and have a long career (without tests)," added Warner.
"Guys see the short term at the moment with all the leagues and stuff around.
"The best way to get value for your currency is actually making a name for yourself."
