I think every one deserves to know about the ZEC Slow Start Rate
Slow-start and ZEC scarcity
In order to give the network and its development some breathing room,
Zcash is implementing a slow-start mechanism for the first 20,000
blocks (or about 34 days). In the event of a major bug or security
vulnerability in the protocol, the slow-start will minimize the impact
as initially, the block reward will be a fraction of the eventual 12.5
ZEC that will be created for each block for the first 850,000 blocks -
at which point, the block reward halves. Over the slow-start period, the
block reward will gradually and linearly increase until it reaches the
full 12.5 ZEC at the 20,000th block.
ZEC distribution rate for first 30,000 blocks
At the moment, this makes the cost of mining much greater than the rewards returned for smaller miners.
This feels like a slap in the face to your most ardent supporters of your work. The least you could do was remove the developer’s reward during the slow start to share that sacrifice. We all have Jack Gavigan to thank for this poorly contrived idea.
The blog post you are quoting is very old (June 1st, 2016) and was written for the alpha release.
This is not even the beta stage yet which might have changed the block rules.
At least that is what I have now come to understand.
I took my info from this page.
Which was written 2 weeks before Zcash 1.0 “Sprout”
To finish answering your question as to when will ZEC be at its 12.5 ZEC (Maximum value per block)
It would be until the first 20,000 blocks are mined before miners start receiving a full 12.5 ZEC reward.
