"Yes, many immigrants who experience poverty in their first few years in Canada do move out of that position."

Correction: "Most" immigrants move out of that position.

"But who pays for the chronically poor, i.e., those whose income is less than the poverty cut-off for five or more consecutive years?"

Long-term they have a lower rate of poverty than the general population.

"Historical" immigration was into a different economy than today's. Tech change may very well eliminate the need for as many "workers" as in the past. So why bring in more people?"

Because there are not enough qualified Canadians for the 'tech" positions those changes engender.

And adding those productive immigrants to our economy creates wealth.

There is a sufficient well of evidence that proves that immigration creates wealth.

I read your citation.

And found it didn't support your claims.

And proved it by quoting your citation back to you. 

Did you read mine?