I dont think that its fair to assume things like these as theres zero evidence that can prove black money is involved during IPL games. Furthermore all IPL players, officials are under constant scrutiny and if anyone was involved then they would have been exposed by now, therefore till credible evidence pops up I feel that we should not spread rumours about IPL unless they can be proved.
You are right we can't say about match fixing until its proven. There is no one who speaks against IPL not even the icc since everyone gets his fair share. The ROI will be low if you rely only on legitimate sources like sponsorship, TV rights etc. Big parties need big return on there investment and this comes only with some fixing.
Your statements say it all. No one speaks about the IPL match fixing because everyone is interested in the share of money which they get from the IPL. Money can make you stand with the wrong

Once after the T20 match against Australia there is no match for Pakistan. As per schedule the next series is against West Indies during the month of June. After the series, Pakistan plays on the T20 World Cup matches. Pakistan have got a lot time to prepare themselves for the T20 World Cup. Some have mentioned the complete Australia isn't available in this series. When the incomplete squad can score 348 runs why can't the same team win the final ODI. So, those are just reasons and the reality is Pakistan did the best.
This is in fact bad for Pakistan. Teams who continue to play are used to the real matches and practice matches would not give you benefit as the real matches can be useful. Pakistan recently played PSL and the team continues the form in the ODI series. Don't think the same performance can be shown if there is break for 2 , 3 months of international domestic cricket.