In that episode where they all come to McCann and are being given there ..duties...so to speak, Hobart dangles Coca-Cola in front of Don as his client.

All seasons long, his existential crisis have been because of the abuse of his past and the anxiety of hiding his true identity,

I felt that Weiner was again trolling like the Hershey pitch breakdown/catharsis, he would do it again...and this time used as a positive, exposing himself as Dick, the real thing..and using that as the idea of calling Coke: The Real Thing tag that was used back then.

He'd come clean, make a great ad/saying by coming clean and not have it be a disaster like Hershey, and ride off into the sunset, as himself, to live life without the fear anymore of anyone having to find out who he was and relieving himself of his past/upbringing, that was the cause for his foibles.