even the developers sleep sometimes
I've already answer to this question; few blocks was mined from developers, but most was mined by someone on the net that started mining before the official annunce. Anyway 5,000 blocks are nothing compared to:
Bitcoin has 504,644 blocks
Litecoins has 1,351,847 blocks
Bitcoin Gold has 509,561 blocks
Bitcoin Z has 74,160 blocks
Zcash has 256,026 blocks
Please focus on:
1) all coins has the same rewards (50 coins)
2) better backport from bitcoin 0.12+ core than others
3) better response time on backports or pulls
4) NO TAX and no founders rewards to mined blocks
5) This is not an Hard Fork so the blockchain was started from zero
I don't know about other specified coins, but what do you mean that BTCZ has 74,160 blocks ?