The simple answer is no, shared parenting is not the default when determining how much time children will spend with each parent.
In the past because the Divorce Act stated in section 10:
Maximum contact
(10) In making an order under this section, the court shall give effect to the principle that a child of the marriage should have as much contact with each spouse as is consistent with the best interests of the child and, for that purpose, shall take into consideration the willingness of the person for whom custody is sought to facilitate such contact.
The Family Law Act is clear however that the only consideration for the Court is the best interests of the child. Because of this the maximum contact principle was applicable only in so far as it was in the best interests of the child.
The Divorce Act was amended in 2018 by Bill C-78, section 7.1 which states:
Best interests of child
(7.1) A person to whom parenting time or decision-making responsibility has been allocated in respect of a child of the marriage or who has contact with that child under a contact order shall exercise that time responsibility or contact in a matter that is consistent with the best interests of the child.
Section 7.1 confirms that when making orders regarding where the child will reside the court’s primary concern is the best interests of the child.
Deborah A. Todd