So although we required a mandatory upgrade between 1.0.7.7 and 1.0.7.8+, this was intended to upgrade instantsend, but not to kick the miners off the current block algorithm.
So the enforcement in this case was set for a protocol upgrade (for sanctuaries) and a soft-hangup on old versions.
This means that blocks solved on prior versions are not discarded unless mined on a fork. So when we get to the point of a 50% upgrade level, those old versions are going to be wasting hashpower. I see we have 63% right now on 1.0.7.1 that has not upgraded.
So this effect will come into play when the 63% solo level drops to 49%. That hash power is going to go to waste and provide more coins for the early birds who did upgrade.
Now here is a Very interesting effect that is happening right now and might answer some of our network questions. I flipped the switch on the pool requiring 1.0.7.9+ to hash against the pool. There are 63% now that are either solo mining or have a private pool, as they are still solving blocks at the 63% level on the network currently right this second (and cant be in the pool as the pool refuses the connection). That explains where 63% out of our 75% is, but we still do not know if its a solo group, a botnet or a private pool.
Sorry for my ignorance, but I still don't get it what is happening now after the "mandatory" upgrade to 1079. From MY understanding a "mandatory" upgrade results in a fork (at a certain block). Apparantely this is NOT what this is, since you write that all blocks solved on older versions are still valid ("unless mined on a fork"). Then you write "when we get to the point of a 50% upgrade level, those old versions are going to be wasting hashpower". How so? On the other mandatories you were afraid that at the key block not enough would have upgraded and therefore the blockchain would fork with the majority on the "wrong end". Isn't this exactly what this is right now? The botnet (and judging by the non-existent pool solutions about 90% of the overall hashpower....) are on a major fork and the pool (so "we all") are the minor "wrong" fork?
Please explain what has happened the last 2 days and how you ever expect the botnet and all the solo miners to update, considering that the current state works just marvellous for them...