It doesn't (want to commit suicide). A plant has all the genetic encoding it needs to become a beautiful specimen. The only things standing in the way are the cultural limitations it has to deal with. If the limitations become severe, the plant might start using more energy than it produces, which always ends in the loss of the plant unless that trend can be reversed. If you're watering while the soil is still wet, it's a good bet the plant is being limited by too much water and not enough air in the root zone. If the plant wilts because it's too dry, that's obviously under-watering. If it ever wilts while the soil still holds moisture - you're likely over-watering - especially if it seems to perk up in the evening when transpiration slows. Beyond that, there isn't enough info to offer much more, but this might help. Al

Check for spider mites, then let's talk water. In addition to spider mites it could oedema which is caused by irregular watering leaning on too much water. You should not divvy up water by measurements because the plant will need different amounts of water depending upon the light and seasons. Water until it comes out of the bottom of the pot and then drain any tray it may be sitting in. Wait until a bbq skewer inserted into the soil comes out clean, like you would check a cake. If it has soil or is wet, wait to water again. Looking at the peek of soil pictured, it looks like the soil is too heavy. You will need to lighten this up with perlite or look up 5:1:1 and gritty mix soils and decide which would be better depending upon how humid it is where you live. I would also make sure there is enough light. Ficus need a lot more light than people think. Since you're in OZ you would need to put it in a north facing window. Not next to or a few feet away but about 6 inches from touching the glass. Since you're going into winter soon I'd also supplement your lighting if possible.

Okay two major problems I'm seeing: Brown spots on leaves that fell off look to be due to overwatering, a lack of air in the soil and/or salt buildup. The reddish spots underneath your leaves are called oedema and can be caused by a number of factors, most often by excessive water retention in the soil (which I think is mostly your problem). Additionally, Fiddles don't really like to be moved, so while giving them optimal light is great, changing their living conditions so frequently can cause them to drop leaves like this. If you can move it outside for the summer, they tend to thrive. Some people even keep them in full southern sun and they love it. Even if you end up burning the leaves and they fall off, they will bud right back out with leaves that are suited to that amount of sun. I put mine right into morning sun today and kind of expect to lose some leaves to this but they'll bud right back out. If I've learned anything from all my research and time with my plant it's this: they are pretty hardy and will bounce back. I don't think you'll lose the plant if correct your watering issue! Here's a link to a post with the holy grail of information about every problem you think you could possibly have. There are several posts about the spots your seeing on your leaves and a guy named Al has some awesome advice I would recommend reading! The post is huge but I would suggest just scrolling down looking for pictures of whatever problem you're experiencing and read responses (that's what I did and I learned A LOT! [https://www.houzz.com/discussions/pruning-ficus-lyrata-fiddle-leaf-fig-dsvw-vd~1458685[(https://www.houzz.com/discussions/pruning-ficus-lyrata-fiddle-leaf-fig-dsvw-vd~1458685)

How to Revive a Dying Lucky Bamboo Check Your Water Source and Stay Away from Chlorinated Water. Keep a Consistent Temperature. Maintain the cleanliness of the Bamboo bowl. Avoid over- and under-watering. Fertilize once or twice a year. Remove any dying or dead leaves and stems. Allow for Indirect Lighting. Insects must be removed from the plant.