I don't think that is entirely accurate...
You still get credit at the retail rate under TOU - so it depends on what the time of day is that you're generating the excess electricity. The pic shows part of my Feb 2018 bill when I was under TOU. You can see they are crediting me different rates for On-Peak, Off-Peak and Super Off-Peak. (negative numbers are a credit)
I do agree with you that they are tacking on $.03 per kWh for 'non-bypassable charges' - but it is only for electricity that you are getting from the grid.
Regarding the 40% decrease - I think there is a couple of things going on if the number is accurate.
First, there was a cap placed on the big 3 electrical utilities. Once 5% of their customers were using solar, they were allowed to change to Net Metering 2.0. So there was a rush for people to get in under the wire. SDGE capped out in 2016 and SCE capped when they hit the July 2017 deadline.
Also, there was some uncertainty about the 30% Federal Tax Credit - and would it be renewed. So again, people rushed to get their systems installed so they could take advantage of the credit. Fortunately, Congress did renew the credit for a couple of years
So ya, under Net Metering 2.0 there are additional fees - but on the other hand, prices have come down on the hardware that should help offset these fees