High reps do not build high strength. They will help to build muscular endurance (a type of strength), but the Impact on strength output will be minimized.
Let’s take this to a logical extreme. Let’s say you start working out and your maximum reps for pushups at one time is 5. Then, a year down the road it becomes 50. Has your strength increased ten times? No, but between muscle development and the building of your endurance you’ve improved. There will be an increase in strength here, but it won’t be anything grand.
Higher intensity shorter reps grant the most strength gains. Also, try to either work to failure or close to it in order to ensure that you’re actually challenging yourself properly. 12 reps is the standard for a reason, do more or less with an understanding of why. More for endurance, less for strength. Twelve even for a good balance.