Altera were roadblocked by relying on Intel nodes. Their new product lines (Agilex 9/7/5/3) are excellent however, despite being 3 or 4 years too late to the market. I've been lucky enough to have early access to them. It's going to be an uphill battle for Altera to win back lost business but based on current performance, and looking at AMDs roadmaps, I wouldn't put it past Altera to take the lead again.