There's still LOTS of room for improvement.
I'm sure someone will correct me if I'm wrong, but I think currently available commercial illumination-class white LEDs are topping out around 150-160 lm/W at useful drive levels, a little higher if you are willing to pay for more LEDs to run at lower current density. Low-cost retail grade parts probably aren't getting much over 120 lm/W, with some considerably less.
The theoretical maximum is often stated as 273 lm/W, if all the electrical energy is converted into light. This is for 'white' light. It varies considerably with color temperature and CRI, and even more if you get into colors. If you want a scientific explanation of this, there are many places to find it. Whether the number is 273, 250, or 300 doesn't materially change my argument.
So if you are getting 160 lm/W and the limit is 273, then you are operating at 160/273 = 58% efficiency. If you were able to get to 90% efficiency, that would be a 55% improvement, or about half again as much light per watt, or about 2/3 as many watts for the same light.
While this kind of improvement may not seem like a lot, it isn't trivial. But more than that, it isn't the whole story. The primary limiting factor on many LED bulbs and fixtures today, as mentioned by Lynx-Arc, is heat. Breakthroughs in efficiency and heat management have allowed the price of 60W equivalent bulbs to drop by a factor of 10 in only a few years. 100W bulbs, while cheaper than before, remain quite a bit higher than 60W bulbs, while 150-200W equivalent bulbs remain unaffordable or impossible.
If the efficacy were increased from 160 to just 210 lm/W, this would allow about twice the light output for a given heat management. This would allow 100 or 120W equivalent bulbs to be priced as today's 60W bulbs, and would allow 200W bulbs to be priced as today's 100W bulbs.
So yeah, lots of room, you just have to know where to look for it.