This is all very true these days, but internal controls were never as strong. I have several experiences in a professional capacity including;
A listed life business with a capital budget of £X millions a year for specific equipment which was always underbudget. The supplier would send invoices for the full amount. They and the procurer would pocket the difference. It was around £2m a year on average over three years.
A large still privately-owned manufacturer had a stock difference on steel of £1m between one stocktake period and the next. After numerous double-checks it was confirmed the stock could only have been physically removed, ie not an accounting error.
An estate agent who with her wider family built a large property company since the 1980's mortgaged the whole lot, plus her home, to buy a commercial property overseas. When the cash was in the bank she disappeared to a small country and never came back. The key to all the properties were neatly labelled and laid out on an office table. These days the banks do more stringent checks before releasing the money.
If you go back about 30 years many large business deals were done in cash. Real cash. I was once at a meeting where £600k was offered to buy a property and the purchaser opened a briefcase, turned it round, and the money was literally there. This was a key executive with a well known building society.
Just to add - not a single one of the above was ever brought to account.