In 10 years I've never seen this happen in finance. Quite the opposite in fact: gifts bigger than a cup of coffee must be reported.
In the private sector it is not unheard of for a salesperson to drop 5 figures on champagne. If salesman from firm A is willing to give an exec or buyer a night to remember once or twice a year, with booze costing one or two weeks salary before tax, and the salesperson from firm B simply sends a "happy holidays" card once a year, it can easily sway that exec even if they believe they are unbiased.
For the really big bribes there are shell companies, which the vendor hires as subcontractor to get "consulting services".
The "CEO" in question is in practice political commissar of the ruling party.
Also, there is always about 10 times more legacy shit than decent new software in any org. That's the ultimate goal for many companies: not even good (let along best) quality but essential because we built something a decade ago to go with it and no one wants to undo all that convoluted undocumented bs. It's sad and I think tech people like me don't "get" it. But it's actually a much better business model than making good software and competing on price/quality.
I worked for plenty of good and shitty software companies. I've never seen bribery. I have seen shitty companies win because they're bigger or older or what was used last time or more polished at speaking to execs who know nothing. One place I worked at made most of its sales because we were a subsidiary of a stock exchange. So people assumed we were safe and competent (we weren't). "No one gets fired for choosing IBM" AND "No one gets a bonus for choosing something better but less well known, quite the opposite, they have to justify it"