The full history of the car audio line isn't laid out in that link.
Phase was purchased by international Jensen in the late 80's. Jensen had originally started out as a high end car audio line, but had been relegated to the cheap name brands. So they bought Phase and Altec Lansing and used them for 'high end' car audio lines.
The Phase stuff was actually pretty good (I owned a PLA 234 and a PLA 2100 amp), but nothing ground breaking.
After a few years, the Phase name fell into disuse, and two different companies bought it for state side and european use. The state side company made really cheap stuff... blister packed 200 watt ILS amps etc.... while the european company makes really expensive esoteric stuff (like the Aliante sub).