Why would ford make a car that DIES OVERNIGHT?

I have a 1999 Mercury Grand Marquis, daily driver.....I will NEVER EVER BUY
ANOTHER FORD VEHICLE....EVER. Anyhow, up until yesterday morning, the
car would start right up and run. The cluster would light up and guages and all
would be operable (digital cluster). I actually drove the car the night before to
go do laundry and get ready for work this week. This was Sunday.

Monday morning I went out to start the car to warm it up to head out, and not
only did it NOT START, the instrument cluster didn't even light up. All other
components in the car lit up. Stereo, inside lights, ac/heater module, the
dinging sound before starting up.....everything else....NOTHING whatsoever.

I've replaced the camshaft position sensor, checked ALL the fuses (good),
changed out the ignition starter switch, the ignition lock cylinder, and recently
changed out the radiator, water pump, reservoir, new battery and attempted
to change the alternator but it kept giving me a battery light in the cluster.

I'm certain that if it were the PCM it would have killed everything in the car
altogether. I have a new starter, but haven't changed it out yet because I think
that it's something else due to the fact that I have do power at the instrument
cluster when everything was working fine the night before. Just trying to see if
someone can lead me in the right direction. I hate missing work. This is why I
will NEVER BUY ANOTHER CRAPPY FORD EVER AGAIN IN MY LIFE.