>DOM is efficient >No it's not, here is the data >something something it doesn't matter because it's fast enough.

So you agree that the DOM is slow? Or, by this logic, can I call any terrible code 'efficient', because if I run it on modern hardware it will still be faster than 'good' code run on machines from 20 yrs ago?

But also, it's not like all this inefficiency is free; every millisecond that is spent running inefficient code requires power. Multiply that by trillions of operations computers are doing every day, multiply that by billions of computers worldwide and we end up with waste of resources that literally change the planet. Not to mention the e-waste of all the hardware we force out of the usage "because it's too slow"