Well I guess we should just give up and not try to do it better this time!
Who says it has to be people with ties to the tech giants? You don't need to suckle at Google's teat to understand the underlying technology and advise on it. And introducing an enforced ban on lobbying for x years (ideally forever, imo) after their government employment ends would help curb corruption.
I think your demographic analysis of those two groups would show greater diversity in the Tech sector than in finance. Look at the variety of opinions on the matter here for some anecdotal evidence.
Early tech people were different. Before there was much money in tech, only sincere nerds went into it.
Since the mid-90s, there've been an increasing number of money-focused techies. Probably still a minority, though.
In fact, before the 80s, finance was also mostly sincere accounting nerds. Then someone got the surprising idea that bankers could be Masters of the Universe.
It happened to doctors too. And lawyers before that.
Yah this time is totally different.