Whilst I agree with SSR in regards to the way in which GS removed the google maps was wrong, I honestly believe that they had no choice.
If they have approx 2,000,000 hits a day on the Google Map servers, they
will have to pay Google a significant amount of money each day which hits their bottom line. Even if they manage to get a very preferentail rate from Google, it still costs a lot of money a day. Standard rate is $4 per 1,000 click - if GS got it for $1 per 1000, they would still be $2000 a day or $730,000 a year! That is a lot for any business to just spend on users just because they want to and assuming they can afford it.
The only benefit regarding maps which is "guaranteed" by GS when purchasing premium is
Use the map view filters to see only the types of geocaches that appeal to you or to remove your hides and finds.
So two days ago, a Premium and a non-premium member saw exactly the same maps. The Premium member had the extra option to hide/show caches based on their type.
Now, a Premium and a non-premium member see exactly the same maps. The Premium member has the extra option to hide/show caches based on their type.
Ergo, nothing has changed

and no degradation of service in a legal sense.
Access to Google Maps was via a Beta maps program and as such GS could/did remove any functionality that did not work or was too costly - exactly the same as any software/service supplier does. They look at their business case and do the maths - it is a cost/price/value issue.
End users can still use Google Maps via the google Maps page or Google Earth. Yes it may be a bit more convoluted but it works.
GS will not release how many people purchase a premium as that is internal business information as a privately owned company, they do not need to do it. However, this could be a smart move on GS - they know that if they just left the google maps and put the price up, people would have screamed. They have had remove the Google maps due to Google licencing model. If they can come to some agreement with Google, they can then put up the price of Premium and a lot of people will pay it (if they do not know workaround!)
C:Geo broke the T&Cs of GC.com and use a lot of bandwidth that GS have to pay for (and bandwidth costs). The cost of their bandwidth will probably be far more than the cost of any cost of now using Google maps. If applications such as c:geo (and there are plenty of others) did not screen scrape, it may be that this may never have happened a GS could have swallowed the costs. It is extremely difficult for GS to code a way to stop screen scraping and it will always go on. Why should I and every other premium member subsidise those that do not want to pay and use "illegal" methods of getting the information ? One of the benefits you pay for with premium is more than 3 caches a day.
BTW, there is a script that already puts the Google maps and satellite back onto the new maps but I am not going to post it here in case it is seen a breach of my premium terms and conditions !
I realise that the words above may not meet with everyones pleasure (and I have my flame retardant suit on

) but unfortunately, this has been caused by a change in Google's T&Cs and not GS's. People should not lobby GS to change things as they can only purchase a service at a certain price and Google have very deep pockets to sue if required.
I am also concerned that the OSM maps may not last that long. I realise that the default is not OSM but a lot of people will use it and I believe that GS is in breach of the OSM T&Cs. Yes they say that they will stand up their own tile server but taking the GS development cycle into account, this could be some time off and it will also cost them a lot more than just the server(s) for the tile server - thee is the additional bandwidth that they will now host that is currently being pushed from your PC to Mapquest/OSM and previously Google.