who started this trend with discount and releasing a remix just to get to no. 1?
I don't know. Discounts have been a big part of the music industry since decades before we were all born. Same with remixes. They're promotional tactics to increase sales, just the same as making a music video, performing a song live, sending a song to radio. ALL promotion strategies to increase sales, and chart as high as possible. Nothing wrong with it, and this isn't something new. Remixes were much more common in the mid-00s than they are now.
I think Rihanna did it. She was wanting to get that #1 hit with S&M but she was not able to, so Brit came in the picture. Mariah and J.Lo did not do it to get a #1 on Hot 100, did they?
That kind of strategies have been in the industry for years, it is nothing new.
I am hoping for Bruno to get that 5th #1.
For J.Lo, from my memory, I'm Real peaked at #2, and then with the remix, hopped at #1. And the rest of her remix album came with a bunch of top 10's, which the originals did not get so far
Mariah..I don't believe she did it to get #1 - I'm not sure about that though, so
edit: Loverboy didn't hit #1, but it was the discount that got it to its peak, #2 - this strategy has been on for years on end.