Just my two cents.
There are two petitions here.
- Resampling the image to 3000 px width, which, of course, will... resample the image from 8819px
Use a bicubic sharper. Wich will give you a nice result.
Quality is not a word to use here. Quality is a process on how you work with your files, yes, the image will be smaller in size, but you want to deliver a good quality image but smaller in size.
And that is it...
Oh, yea... the 72PPI.
My analogy of setting an image to 72PPI is like buying a new car, tires, checked, engine, checked, paint, checked. All good...
And for the 72PPI? Just take a post-it and write the number on it and paste it on a window.
It seems the company guy wants it for a website... and a website takes that post it and throws it away.