The phrase "all this illustrates" is correct and usable in written English.
You can use it to indicate that the preceding information or examples provide a clear demonstration or explanation of a point being made.
Example: "The various studies conducted over the years show a significant trend in climate change; all this illustrates the urgent need for action."
Alternatives: "this demonstrates" or "this shows".
All this illustrates the inconvenient truth that rapid financial innovation over recent decades has made history an imperfect guide.
All this illustrates, we believe, that the recovery process is far from assured and shareholders may have to endure further cost hikes.
All this illustrates the hazards of being the world's fifth-largest economy, with a large part of our economic policy contracted out to others.
All this illustrates the existence of tension between the interests or protection of the community, respect for individual liberty, and citizen responsibility.
All of this illustrates the pressures companies face in a bull market.
All of this illustrates Green-Wood's evolving role as a cultural institution.
All of this illustrates that the conventional wisdom — that Class A shares are the "best" for investors — is not always wise.
All of this illustrates that a government without a majority can still be a powerful and effective force, although its survival rests on the continued acquiescence of opposition parties.
"What I think all of this illustrates more than anything is the theory that the mental side of the sport is far the more important to success, maybe by as much 90 percent," said Brandle Chamblee, the former player and Golf Channel analyst.
Uri Zeevi, chief marketing officer of Seedo, said that all of this illustrates how, "[by eliminating] the criminal component of marijuana, governments could regulate production in a more secure manner, robbing criminal gangs of their power and as we show in this study generating enormous tax revenues for the development of countries".
As all of this illustrates, the mainstream press simply refuses to give equal time to the atrocities carried out by the U.S. and its allies, while instead focusing on the abuses (both imagined and real) of the U.S.'s ostensible enemies.
