Have modern glues and clamps rendered this ancient joinery technique obsolete?

Absolutely not.

Drawboring is one of the simple reasons that so much antique furniture survives today, some of it as sound as the day it was made.

What is drawboring?  It’s a technique that greatly strengthens a mortise-and-tenon joint, transforming it from a joint that relies on glue adhesion into a joint that has a permanent and mechanical interlock. In essence, you bore a hole through both walls of your mortise. Then you bore a separate hole through the tenon, but this hole is closer to the shoulder of the tenon. Then you assemble the joint and drive a stout peg through the offset holes. The peg draws the joint tight. Drawboring offers several advantages compared to a standard glued mortise and tenon.