Before this degrades into an argument over semantics, let me help you define speed. You want to be faster than your competitors in the 800m and up and you want a faster kick at the end. Pure speed is more for the 100 and 200. Top 800 and 1500m runners don't need to run 10-second 100 meters.
That said, strides are good, as you described.
To have a kick at the end of a race, I believe it's helpful to practice kicking in your interval workouts. Short intervals of 200-300m where you pick up the pace over the last 70m or so seems to work wonders for the adults I train.
For example, on 3 sets of 3x300m, run the first interval normally until the last 70 meters, then move your arms much faster to finish. (This increases cadence because the legs have to follow the arms.) The idea is not to run a lot faster, just get the legs and arms moving faster. You may have to chop your stride a bit to keep from running a lot faster. That's okay. This is a drill for cadence, not speed.
On the second rep, run normally until the last 70 meters, then forcefully push off harder until you're almost bounding. The idea is not to run a lot faster, just get as much push off as you can. You may have to slow your cadence to do this. That's okay. It's a drill for push off.
On the third rep with 70 to go, combine the two previous drills. Push off harder and increase cadence. This time, you will run a LOT faster.
Reps 2 and 3 will hurt, so take an extra minute or so during your recovery if you need it.
Once you can handle this workout, increase the kick part to 100 meters instead of 70.
Question: Why focus on moving arms faster in rep #1? 1. In a race, you legs will be tired, but your arms will be fresh. 2. Focusing on your arms gives your oxygen-starved brain something to do. 3. It gives you the confidence that you can run hard while letting someone else set the pace and then outsprint them over the last 200m.