Indeed.
One would expect losing more than half of their planets and every single ship they started the war with should make them more... amendable in the peacetalks.
Not so.
In my current game,,the Terrans jumped the bandwagon (I've been at war with one race or another since turn 17 on a gigantic map) opting for Bean- and Massdriver weapons.
Since everyone in the bloody universe except me (who perfers guided rockets) are totally in for slinging pellets at eachother I already had decent defence against MDs, so a few turns of research rendered the Terran fleet obsolete.
Skipping to the end of that campaign,,the Terrans are left with perhaps a quarter of their initial planets and only the pityful few Defenders they have managed to build after I sent them close to bankruptcy by choking their trade and eradicating anything that could be taken as an excuse for a Starbase (only starbases on the map are either mine or those I have given to my sole ally,,the trusty Arceans. Well,,not so trusty really,,but least they aren't waging losing wars AGAINST me heh).
One could belive that peace would be easy to get,,right?
Think again...
My initial demand was for them to give me a 21 class planet (which by chance had Aphrodisiac on it... constant invasions tends to exact a heavy toll on the population

which was refused outright.
Out of curiousity,,I experimented what it would take to have some calm:
*5723 bc
*873052 influence points
* 29 planets
* the whole Missile techtree
* a third of my fleet and half my Mining SBs
Ain't gonna pay that...
Hence I invade the undefended planet I wanted in the first place...
...and promptly get a gleeful message from the Terrans that they in a last act of defiance have surrendered the remains of their empire to my ally the Arceans