It would be beyond retarded to the point of lunacy if that was the way it was done My bet, its not. IB did not last 35 years by being that stupid
Even the best written code will be develop inefficiency over such a long period. Design wise , and who knows what else A complete rewrite would be very expensive, and produce little net benefit , other than to the complainers
IB must really throw their garbage software into dustbin and release an fully new software which fits in 2020's condititions. Look at Think or Swim or Webull. They have amazing fast and beautiful software and we IB users are using a software from Windows XP. IB's CEOs or directors must be ashamed if they see the other broker's softwares...
I presume you are not a programmer... Companies spend billions on bug fixes yearly. Rewriting any multi million line code from a clean sheet gives a far better vision for the future than remain the same old. Staying with the same buggy code to me is a "union" style thinking because this would eliminate sub performing coders from the company. Just look at how companies such as Google/FB/NetFlix/etc spend on their apps which won't last some X number of years. A perfect example here is the "good riddance" Google Music. I am not suggesting Google Music was a poorly written app.
Too many people here without any software development experience commenting on how software should be developed.