Taxes aimed at changing behaviour are generally considered to be bad taxes.
Firstly, you may not like the outcome. Changing the entire time-and-capital structure of an economy is Serious Business and is going to be utterly unpredictable (if it were predictable things would be more stable. They're not).
Now, suppose it turns out to be a dumb decision. For example, say that some unforeseen feedback loop pops up between overdraft facilities and capital now sitting long-term because of tax changes. Suddenly overdrafts become even more difficult for small businesses to obtain and voila, new cash crunch.
Even if it does more harm than good, you've created a powerful constituency for it. Bond market funds, index funds etc are now all in favour of the new tax rules and will lobby with great vigour to keep it.
Now, this is true of every tax ever. But the reason economists counsel against taxing for non-revenue policy purposes is because every tax has externalities that are unrelated to the direct incidence of the tax. You want to minimise those as much as possible.
Incidentally, the tax system already has consequences. For tax reasons that I simply don't understand, Australian corporations tend to be keen on paying healthy dividends and American corporations focus more on driving up the stock price.
> But that is only a mechanical property of the progressive tax scheme (lower tax for lower incomes), which makes the redistributed money more likely to be spent
The Australian experience has been that instead of spending the money, Australians are using it to pay down debt. Fine as far is it goes, but hardly the pump-priming that everyone was hoping for. There has been a seismic shift in debt/spending preferences across the population.
> but a new kind of shock based on a slowdown of the progress of technology
The long term trend of American GDP is stunningly linear[1] (edit: log linear -- actually exponential, I fail graph-reading forever); the only real deviation in the past century has been the Great Depression and WW2, a pair of connected economic earthquakes. We're talking about the 120 year period which included the widespread use of radio, television, highway systems, air travel, computers, the internet, modern medicine including antibiotics ... the list of literally revolutionary changes that quickly become blasé is very long indeed.
Yet what we see today as monstrous fluctuations are within trend. Perspective matters (cue someone talking about the past 5000 years ...).
[1] http://skepticlawyer.com.au/2012/10/27/the-ever-sharpening-c...