Thyristors (also known as the Silicon Controlled Rectifiers or SCRs) have come a long way from this modest beginning and now high power light triggered thyristors with blocking voltage in excess of 6kv and continuous current rating in excess of 4kA are available.

http://www.nptel.iitm.ac.in/courses/Webcourse-contents/IIT Kharagpur/Power Electronics/PDF/L-4(DK)(PE) ((EE)NPTEL).pdf

They are also widely used as fast acting protection devices in DC power supplies. The switching speed of thyristors is very fast and they are able to switch from fully off to fully on, typically in 1µs.

http://www.learnabout-electronics.org/diodes_06.php

Price is probably the main concern?