Here is the process to add a View All link into your e-commerce product list page.

Navigate to the below folder structure & override the below page to customize: packages/e-commerce/blocks/product_list/view.php

Find:

print("<span class="pageRight"><?php  echo $paginator->getNext(t('Next'))?></span>");

and append the code:

print("<span class="pageRight show_all"><a href="<?php echo $this->url($c->getCollectionPath());?>?search=1&product-list-search-core-commerce-products=Search&numResults=100">View All</a></span>");

That's it. You are all done.