Although this has been a rare occurrence in the past it is becoming more common as some blocks of units/flats deteriorate beyond their highest and best use of the land. But its not easy. In order to be successful 100% of owners must vote to do this at an extraordinary GM of the body corporate. (Some States are moving to legislate to lower this to 75%.) That said, getting 100% of people to agree on anything is akin to herding cats. Then there is the moral issue under the 75% move. There are those older residents that may have owned and lived in the subject property all their lives, and have an emotional attachment. A question for another day perhaps, but forcing the elderly to sell does not sit well with me.
As to the apportionment of the proceeds of sale, that would depend on the unit entitlement and unit liability as set out in the schedule (strata title). Or number of shares if the units are owned under the company share system. But here's the rub. Some residents could justifiably argue that they have made significant improvements to their unit (new kitchen/bathroom etc), so their 2br unit is worth more than their neighbours 2br unit. In this case a sworn valuer might be called in to arbitrate, but that too would need to be voted on by the body corporate. Or it may be that the subject purchaser is forced to treat with the owners on an individual basis.
