Frankly, comparing BA with low costs like Vueling is non-sensical. They don’t fly any of the same routes. The only useful comparison is with Easyjet and Ryanair who cover a number of the same routings.
Whilst BA retain numbered seating (forever, I’d imagine) and the other two go for ‘free seating’, the experience on BA short haul economy will always be infinitely better. No unseemly scrum at the boarding gate, no racing from the bus at airports with ‘bussed’ gates, no being separated from loved ones (unless you park yourself at the gate a ludicrous one hour early.)
Once you add-in Ryanair’s and Easyjet’s fees, there is often little or no difference in the fares when compared to BA.
If anyone honestly tells me that they prefer the free seating mayhem to save a few pennies, they clearly need their head examined.