My big4 experience is technology consulting, I started my career with Big4 outsourcing in Asia, more than 2 decades back.
Yes right now economics has hit the big4 particularly the management/technology consulting businesses within big4. What I have seen traditionally the accounts/Tax audits businesses always need new employees all year round. I have read many articles that AI is taking over a lot of the Audit roles but I'm yet to see that in action. Now on the question on finding jobs, It depends on the job level one is looking for, there will always be Analyst level (under 3 years) and consultant level (under 8 years) openings. Yes number of jobs are lower than usual due to poor economics as Canuck says but there is still a few jobs at-least to replace the churn out. However if one if searching for a Manager/SM/Director level yes the number of openings will be almost none today, often need superb/niche experience/skills and takes many months to even years to get in.
Keep in mind Big4 often try recruit one at a level or 2 below the person's market job level, one of my peers a Sr.Director in a smaller firm was taken as SM in EY last month. He had to woo multiple partners in multiple firms over many coffees, conferences etc... He was doing that for almost a year.
As the Big4 pay is not competitive, work culture needs employee to grind long hours etc... the laidback / easy come /easy go Canadians often don't join or tend to leave after internships. Hence Big4 usually have a large immigrant employee base atleast in the non-government business. Federal work needs citizens, even most province government work need a PR at least often.
My advice for a job seeker is to keep networking with folks 1 or 2 levels above the designation you want to join at. Add them in LinkedIn, ask them out for coffees etc... that is the key to get in and to grow after getting in. Of course the employee you network with has to be a SM or above. often they are only hiring managers.
Anyway thanks!
