As per the diagram, it's not exactly "wasted".

The Kva is the amount the supply authority are generating.

If there were no capacitive (leading) or inductive (lagging) with the current, reactance in the load, Kva would equal Kw.(as is mostly in DC)

Since it is not, then the load dictates the difference.

If the load is mostly inductive, say a workshop full of choke style welding machines, then the supply authority Kva is much greater than the Kw.

As most of the meters are Kw meters it means the supply authority must generate a wack more power overall to get this Kw level, but only get paid for the latter.

Such is why, large inductive installations must install capacitor banks to at least partially bring this lagging power factor somewhat closer to unity.

It is why the choke style fluroscent lights had capacitors installed. Not so much for one installation but overall, it adds up.

Monduran pump station in Aus with it's 4 x 3.3kv 400hp motors had it's own on site capacitor banks to bring the pf up to somewhere near 0.9.