Did you read my code?

Seriously, keep in mind Magi is 10 years old and so is its white paper and the M7M algorithm. The white paper, like many in crypto, reads more like a
sales pitch than a technical description.
Block reward adjsustment is nothing new but is a property of the coin, not the algo, and it applies to the entire network, not individual miners.
If Magi worked as you suggest it would destroy pool mining because a pool appears as one miner to the blockchain and would therefore be
penalized as a whale.
Also keep in mind hashrate is an artificial metric, it's calculatred based on submitted shares or blocks over time. The blockchain network only sees the submitted
blocks, it can't tell how they are produced, whether it was one big CPU, a pool of small CPUs, or simple luck.
The fact is mining on a phone is done with the CPU, and competes with any other CPU, big or small.
Conversely any POW coin that can be mined on a desktop can also be mined on a phone if the software is available. Real POW mining on a phone should be avoided for
reasons that I have articulated elsewhere.
"Phone only POW" is just a marketing lie.
Edit: the only thing unique about M7M is the use of multi-precision arithmetic which makes it unsuitable for implementing on GPUs.
I understand most crypto projects exaggerate their features to help attract investors into them. But Magi is not one of them. The M7M hashing algorithm, although old, works as described by the original dev. It's not simulated mining (unlike Electroneum and the likes). I've once tried to mine XMG with a high hashrate, only to receive 1 XMG per block. Did the same with a low-powered Android smartphone, and got a higher reward in return.
The idea is to eliminate the monopolization of pooled mining and incentivize solo mining. A great way to encourage decentralization of the network, imo. Despite Magi's design, that hasn't stopped pool operators from running their own business. They still win with the fees they collect from miners using their pool. But at least, the algo works as intended.
What the project needs is a little tuning to keep it on-par with the latest advancements in the crypto/Blockchain space. With active development and innovation, CPU-mineable coins like Magi can make the difference. So I would not generalize and call all mobile-friendly PoW coins a scam. It's just that there aren't any serious developers working on making mobile mining a reality. Who knows? Maybe things will change in the future...