Will analog electronics be replaced by ADC, DAC in future?

Well if the question was framed in a matter to ask "will ICs (integrated circuits) continue to decrease the amount of on board discrete analog components and circuitry" the answer would be a definite yes. But the fundamentals of analog electronics will always apply and there will always be some design cases where discrete analog components and circuitry will still be used over a chip solution.

One only has to look at a modern DDS chip to see how much discrete analog circuitry for RF applications can be replaced with a single chip and a few external filtering components. For example:

http://www.ebay.com/itm/New-AD9850-module-modest-capacity-AD9851-DDS-Function-Generator-up-to-40MHZ-/400422353936?pt=LH_DefaultDomain_0&hash=item5d3b083c10

Lefty