All that technology investment is not a waste; it allows firms to condense money out of information asymmetries with ever greater efficiency.
Edit to add: if you prefer industries that build "real things" then look at the revenue that HFT delivers to companies who make high-speed networking and computer equipment.
My post was comparing the current system that allows millisecond scale trading with a hypothetical one that slows trades down to something on the order of minutes. Your observation that people are willing to pay to exploit information asymmetries in the current framework doesn't address the question of how my proposed change would affect net economic value.
Your proposed change would reduce the benefit because it would eliminate the profit (wealth) that HFT firms create.
Your proposed system is not hypothetical; it is how all trades used to happen. HFT did not arise from nothing. People developed it because it created new profit in addition to that generated by slower trading.
If HFTs were all 100ms slower, I wouldn't care. But if HFT 1 is 100ms slower than HFT 2, then HFT2 will capture $0.03/share and HFT 1 captures nothing. It's a wasteful arms race. It's also fixable simply by eliminating the subpenny rule.
http://www.chrisstucchio.com/blog/2012/hft_whats_broken.html
That said, there is and always will be an advantage to players that can respond more nimbly to changing market conditions (news being one input to this) and there is no inherent problem with that (and there may be lots of positives to the market as a whole).