I personally believe that vested status quo interests engage in a certain amount of "at a loss" dumping practices; however, at some point, their efforts no longer have an effect because they are no longer able to get their hands on a sufficient number of coins in order to negatively affect the price... and the upwards momentum becomes too great for their dumping to have a material effect.
I am not sure whether bitcoin has reached such a stage yet, in which vested interests are having difficulties acquiring coins.... but it sure is possible.
Indeed. The supply of coins is limited.
While they can print more fiat any time to buy coins to sell at a loss, they're ultimately just adding more demand to the market while supply remains the same or decreases.
This is bound to push the price even higher. For them, this may be an expedient way to try to slow the price increase, but in the long term, it's folly.
Probably we agree overall about the likelihood of such a practice and maybe even a certain level of futility in attempting to keep it up, yet my theory regarding the best logistics for such is to work out off exchange deals to get coins (either regularly or acquiring through various off exchange sources), and then to dump such coins on the exchanges to bring down the price.
In such a practice, they are attempting to push downward more than upwards, but such a practice becomes more difficult if they are having more difficulties getting sufficiently large quantities of coins off of exchanges... and then even those off exchanges coins become more and more expensive which then indirectly drives up the prices on exchanges (even though that was not the original intent).
One way around this whole matter happens to be if some exchanges end up being corrupt and reflecting books of more coins than they actually hold - but maybe even that practice becomes more and more difficult because some users may figure it out that they don't really have the coins (or at least not a sufficient quantity of coins to satisfy all account holders).
Another attempt could be to engage in a kind of leverage to attempt to push the price down by buying coins that you do not have, and that could be both expensive and even lose effectiveness if the price pressure remains upwards, despite dumpings.