The answer is yes. Most of the new smaller providers are already using the IP network. It is therefore not an additional burden for them. Those that are not can rely on their upstream provider to handle this aspect on their behalf.
We have not yet received any complaints. To my knowledge, no provider has told us that this new requirement is too much of a burden.
The only hitch reported does not come from the industry side. For the STIR/SHAKEN technology to work, certain technical capacities are required, including software and switching equipment. There also has to be an IP interconnection agreement. It's with things like this that the smaller providers might sometimes have to wait longer, which is only to be expected. Agreements with the major providers like Bell Canada or Telus are generally in place earlier than for the smaller providers.