It is not true that reliability requires old-style engine design, it's more a question of cost. Modern jet airliners (their engines but also really everything about them) have a ton of complexity, including a myriad of electrical control systems, yet they are no less reliable.
It's just that this is not a fair comparison because manufacturers of said airliners have more resources for R&D.
It's just that this is not a fair comparison because manufacturers of said airliners have more resources for R&D.