Yes, the propellant "fuel" is for orbit keeping. The satellite electronics are powered by solar panels. deep space probes are usually nuclear powered, never earth communication satellites; they are solar.
It is really the life of the propellant that decides the useful life of a satellite.
That's all basically correct. There is lots of study going on as to how we can keep satellites on orbit longer, as our ability to make electronics that last a long time in space has exceeded our ability to keep satellites in orbit. Technologies such as on orbit refuelling and ion thrusters may allow us to fix the issue. There is also a limitation with regards to how much weight current launch systems can put into GTO.
One of the original proposed uses of the Space Shuttle was to service, repair, and retrieve satellites, but like most of today's electronics it cheaper to replace them.
So Anik G1 is to goes up and we hope it doesn't get hit by any space junk!
There are other limits to useful satellite life, such as decline in transponder output and power failures. Considering the environment at 24,000 miles, most satellites are not going to be fully usable much beyond 15 years. They can be hardened against radiation and damage from space debris but weight, again, limits that.
The real problem is the amount of time it takes to deploy a new satellite. They are very complex, custom built and the process takes years. It is possible to move retired satellites into place to make up for damaged or partially failed satellites in use. Bell did that with N1 and N2. (N1 operated beyond it's design life with partial functionality and N2 suffered a partial failure soon after deployment.)
Nothing to apologize for, because I didn't say/do anything wrong or offensive.
We are talking about TV satellites here (Bell, Shaw, DirecTV, etc...), and it is my opinion that the Space Shuttle, being a Low Orbit Spacecraft, was not designed to go up to 35,000 km. and retrieve T.V. satellites for service, replacement, etc...