Hi there,
The model portfolios are definitely ongoing and are revised twice a year. At that time, we do re-balance the portfolios and sell stocks we believe no longer fit, or will buy new ones that we find attractive. In terms of the MC portfolio, the stocks as presented all make excellent long-term investments. The long exception in terms of expensive stocks would be, as you point out, Shopify.
However, it might surprise you, but SHOP at $1,314 is starting to look attractive again. It has been consolidating and typically when it sees big drops (as it has recently), it has proven to be a buying opportunity. SHOP has one of the highest expected growth rates on the Index and as such is deserving of a premium. Not that an investor should run out and buy the company at these prices, but don't discount it either.
An investor could also swap out SHOP for another tech company of their choosing, but worth noting the entire industry has run up in a very big way (not just SHOP). Investors can either chose to add at these levels, or wait for a further pullback before investing in the industry and focus on building other positions. The risk however, is that investors miss out on the strong momentum the industry is experiencing. As we've seen, the appetite for tech stocks appear to know no bounds.
Mat