the only main winners of this coin is the first round participants
FIFY.
You could say the same about any successful project.
In the end everyone who participated first always got the most out of it.
But they took the most risk as well, in this case just the time to take part or buy some BTC to take part.
I think there's a bit more to it ...
Let's assume a first rounder who linked 10 BTC, they got a bit more than 14 GB, let's make it 15 GB, in the 2nd round they got 1.5 GB + 625 MB, let's round this down to 2 GB so in the end they have 10 BTC + 17 GB.
Let's assume someone who came in before the second round when the price was stabilizing around 0.05 (and that's quite late cuz there used to be GB to grab at 0.008), let's make it 0.06, so 10 BTC would've bought a bit more than 166 GB (let's stick with this one), after that there has been plenty of opportunities to sell at 0.08 or higher, let's say they wanted to recover their initial investment, so they would've sold 125 GB (at 0.08), recovered 10 BTC and kept 41 GB => Better than a 10 BTC first rounder.
Of course this involves way more risk, a strong belief in the growth potential, hodling a bit (some days ^^) and some luck (yet the ones who bought at 0.008-0.01 and sold at 0.1-0.2 were probably the luckiest

).
What I want to say is that opportunity is still here, and first rounders are not necessarily those who will make the most out of it ... (maybe whale first rounders)