Not sure if you were really familiar with trading business, especially construction. For the contractor to supply material to main con, the quotation is always has a lock in period stated within how long the period the material supply will maintain at certain cost. Nowadays 1 single project will segregate into difference phase and the later one always sell at higher price per square feet. However when the main con is seeking quotation of raw material, the quotation will always lock for certain period or lock in per phase. Any cost changes of the raw material the supplier cannot charge to the main con, they have to absorb the hike. At best the supplier can do is revise the quotation for next phase, but they have to take the risk that they may not get the letter of award from the main con to get the deal because of intense competition.

However in perspective of developer, the new phase price always increase 10% or above but the revise material cost was increase maybe less than 5% or sometimes no increase of material cost. In fact it is not often happen increase of raw material cost. Most of the raw materials are from local market rather than import, if it were import the raw material may has to increase due to currency issue or duty. Developer or agency like to use the excuse the price increase because of raw material cost increase, it come be true but chances is low.

For those developers on hold the project and eventually went bankruptcy, these kind of developers likely has financial problem due to "rolling", never because of the material cost. The word of rolling applied not only in property but also in most of the sector. 1st developer gather a small capital (partially from bank loan) start up a small scale of development, after the 1st project sold about 30%, they will pay to the bank and at the same time asking for another loan with higher amount. After the 2nd project launch and sold about 30%, by that time the 1st project may likely sold about 50%, the developer will start paying to their supplier (supplier always give term to developer, that's industry practice). The 2nd project can be started few months after the 1st project launch, so that they can seek the fund from 2nd project to fund to the 1st project. And the developer will keep going this process started the 3rd, 4th and more projects, by that time the money is rolling bigger and bigger, of course the debt also become higher and higher. Always take note many developers will setup new company for their new projects, if 1 project got problem they can shut down or declare bankruptcy (sdn bhd business entity, director worry free).

So when 1 project got issue, maybe due to low purchase rate, land problem etc, and cause the progress become delayed, the developer will evaluate whether to continue the project or how. Delay handover will cause the developer pay the penalty to the purchaser meanwhile it will stuck the "rolling" process. Some big player may still go ahead complete the project with many unsold units, this action need a lot of funding and it takes the other projects' money to cover this problematic project. So for some small scale developers will lack of funding they will declare bankruptcy right away.

This is my own opinion, not to offence to anyone.