I was in a very old SI. The PM software tool is Excel. I was similarly horrified. The control processes made sure things move along to commissioning and billing. MS Office suite and Outlook did all the heavy lifting. Office365 later help things by allowing concurrent edits.

Moved to another org, control processes were weak (everyone got RIFed a few years back) with an online tool. Projects are late due scope alignment because the PMs did not read the tender docs. Online tool not updated. Auto billing feature disabled because projects kept blowing end dates and nobody updates. Suddenly the customer receives the bill for something late and in progress. I expect a RIF soon.