Usually I get between 5 and 8K depending on the drops. It varies a bunch. I have a couple times a little higher but mostly towards the middle of that range. Today I picked up two launch chests so that added 4K plus the the 5 coins per click so it was a slower rate than normal.
Yes, that's really low. Not sure what to suggest which will help increase your figures. There may be something going on in the background, within the game, which has an effect on your score rate? Although you are on level 60, perhaps you need to be further along, in terms of buildings and structures which will increase your income. Not really sure what else to say which will be of help to you.
The following serve me extremely well when visiting my neighbours - Green, Blue and Red Launcher Pads, Planitariums, Training Centre's, Mission Control Centre's (L3), Research Labs and Astronaut Acadamy's. They are the only locations I really focus on when collecting items and chests, as well as coins for completing collections - the rewards for completion vary from 150, 300, 800 to 2000 coins - which all add up to healthy totals.