Good question Deepesh. Surely, growth for a traditional marketer is limited if s/he doesn't acquire digital marketing skills.
Contrary to what a lot of people have started to think, digital marketing is not replacing conventional marketing. The contribution of digital is growing in overall marketing. In short, marketing is becoming integrated. And there's an increasing demand of senior marketing professionals who understand both conventional and digital marketing. For the same reason, a traditional marketer with relevant digital marketing skills can really grow well to take up senior marketing roles in high growth startups and large corporations.
A specialist digital marketer will also continue to grow as there would be increasing demand for such people. Btw, soon we will stop talking about digital vs traditional marketing :).