Triumph has said they are going to come out with an MX bike and compete in AMA MX and SX. That has got to be a huge investment for them, so they must be serious.
An old timer brought a late 60s Triumph MX bike to Carnegie one time and I did a lap on the track with it. The suspension sucked but it actually railed turns pretty well and didn’t feel heavy. Triumph has history in offroad, they were the kings before the Japanese factories got into the sport.