Big cactus identification and how long does it take?

Question

I found these huge cacti in a garden-center, the two on the right. The largest in the back was over 1.5 m in length! They were a little bit too expensive, so I thought maybe start from seed...

What species is this, and how long does it take before they are as large as these? And how to get them this big, is that possible as houseplant, or do you need a greenhouse for this?

Edit: I went back to the garden center, and found names on the labels! The two tall ones on the right are indeed South American cacti. They are called Trichocereus pasacana, a.k.a. Echinopsis atacamensis. So Echinopsis was a very good guess (see accepted answer). The two on the left were Pachycereus pringlei, just like the answer suggest!

The little one between the two tall ones on the right was sold, so I couldn't see what it was.

Answer 1

The two plants on the left are either Carnegiea gigantea or Saguaro or Pachycereus pringlei or Mexican/Sonoran Saguaro. They look very similar at this stage.

They look to be 10-15 years old. My mother bought a P. pringlei this size 7 years ago and it is now over 8 feet tall and flowered this past spring. They grow arms more quickly than Saguaros. Saguaros on the other hand grow more slowly.

The tall plant front and center might be Echinopsis terscheckii. The spines look a little sparse to be E. terscheckii, but spines are not a reliable indicator of species. This plant would also grow into a very large columnar cactus.

I have no idea what the plant in the back right it. I suspect it's another South American columnar (there are LOTS of them).

How quickly a cactus grows is dependent on a number of factors including sun, temperature, water, nutrition, etc. There's no way around it, you can't really push a Saguaro. You might get a P. pringlei to 8 feet in 10 years with perfect conditions and effort.

They all look like nice, healthy, well grown plants. I suspect the E. terscheckii is a rooted cutting. The picture isn't clear enough to ID the little plant. Stetsonia coryne is a possibility.

Except in very unusual circumstances, you won't grow a plant like this in doors in pots like that. Outdoors is possible, depending on where you live.

I"m curious, where is this garden center located?