PH may not be a such a detrimental element of soil growing for sure, but to say to throw away the PH/EC testing equipment is like throwing the baby out with the bath water! PH is the scale on which all elements take differing forms based on acidity or alkalinity and not every plant is going to be able to utilise higher or lower PH's the same. I tell ya what my Hydrangeas LOVE low PH! they go beautiful and pink out in the garden when I feed them super acidic but my other leafy greens in the same garden do not like it. I think as a grower it pays to have an over all understanding of how PH and EC/TDS effects growth! The PH pen saved me when the doser on a fertigation system was faulty, I checked the PH and noticed a constant decrease in PH which lead me to test the doser and see that the EC/TDS was super high! Rather than spot it when there was burning or crop failure my little pens enabled me to fight the problem quick, thus saving a few bob worth of plants (shrubs, annuals, perennials, potted colour)
It shouldn't be one side of the fence with this stuff. A good grasp on all aspects in horticulture/agriculture enables you to work smarter not harder. You dont have to employ everything you learn out in the garden!