I’ve given a lot of lessons, to both pros and amateurs, who feel they are losing distance due to decreased clubhead speed. While that certainly may be a big factor, it’s really not as important as centeredness of contact, hitting the “sweet spot”.
For instance, I have been outdriving a friend by about 35 yards in the last couple of years. My clubhead speed is right at 100 mph, and my ball speed is 145 or so, giving me a carry of up to 250 yards and a total drive of 260-265. My friend, who is hitting it about 230, assumed he was swinging at about 90 mph. When we tested him, he was 95, and even reached in the high 90s with a couple of drills and swing thoughts. His problem was contact. He virtually never hit the sweet spot, and usually missed it by 1/2 inch or more. For a player who hits it 250ish, if you are 1/2 inch off center, you lose 17-18 yards. If you are one inch off center (very possible), you lose 35-40 yards! You would need to pick up 15 mph to offset that mishit, and that ain’t going to happen!
Check your clubhead speed, multipy by about 2.6 yards and that will give you your approximate driving distance on a solid hit. If you are falling well short of that distance, get some impact decals (or Dr. Scholl’s foot powder in a spray can) and check your impacts. If you are consistently hitting the ball on the heel or toe, for instance, adjust the distance you stand from the ball or where you align the ball on the clubface (a lot of us align the ball on the heel and then hit it there!). You may pick up 15 or 20 yards without swinging any harder!