Please check out the whitepaper v1.0. Our recent research on 50 blocks after fork confirmed that CPU miners (window, linux or mac desktop/laptop miners) obtained 36% of block rewards, ASIC only mined 66% of block rewards. CPU mining rewards are significant.
And what is the reason for that? Could this be overtaken by ASIC miners any time if there were enough ASIC miners used to mine this?
No, DynDiff on scrypt is ASIC-restricted. This algo does not ban ASIC, and we welcome ASIC, but ASIC will do and is doing poorly on mining NENG. Currently the dominant mining rig is GPU, followed by CPU or ASIC. I do not have full data of research to back this, but my estimate is that currently 50% blocks are mined by GPU, 30% by ASIC, 20% by CPU miners. I will publish a new research addressing your question if significantly more ASICs joins NENG in the future. In short, no, not even big ASIC miners from Litecoin/Dogecoin can overtake NENG now at my quick calculation. Not worth it, too costly is the reason.
Actually the big ASIC miners do very poorly, only the small ASIC rigs are OK and are doing better. krypton93 already mentioned that his asic L3+ only getting a few blocks while his 4-core CPU mined 400+ blocks.
The reason of this was explained in white paper v1.0. In nutshell, ASIC miners have weak points, they are like lions, slow moving, powerful. but Lions can not run fast, can not climb trees. Same logic, DynDiff explored the weak point of ASIC and restricted ASIC mining rigs in this new update.