Look up dual-pixel technology on canon DSLR. Sony and Fujifilm uses it on their system-camera's too. (See Fuji X-T2 or Sony A7 for example). Pretty neat technique placing phase-detect pixels on the sensor.
If you look at the 5000$ Sony A9 it is comparablr to the most advanced DSLR separate PD-AF systems.

That said, contrast detect have come a long way too. Optimisations and improvements to the algorithm made it significantly faster than it used to be.