I have never opened 1000tabs in chrome but I can manage 100-200. I've noticed that a lot of this responsivness comes down to extensions. If you have only one bad extension it kill the performance of chrome. Another thing are ads ofc or sites with lots of (poorly written) javascript, but with ublock origin Chrome works fine for me.

Also by 200 the GUI of chrome starts to annoy me so much that it forces me to close some stuff. I've tried a few extensions to deal with this but I've chosen to keep it clean and below this threshold instead.