It’s not fair to say contractors are cheaters, the problem is the accountants. They would want the bus solution at the cost of cable but install price of bus.
Another problem is that the plant engineer may design to meet existing technology so if its been wired for 10 years and you start to add on do you bus or do you wire? Is it a development project and what happens when you decide that the project is no longer needed because we have a bigger idea (requiring bigger loads)?It is quite easy to run temporary installed cabling that could be hung later.
No easy answer to your problem but don’t call contractors cheaters as contractors have to complete a task before payment. The one thing I will say is that contracts are poorly defined and audited/supervised