Is it normal now to have the interviews spread over weeks?

I have been interviewing with multiple companies during the last month, and one major difference I noticed compared to my last job search is that most companies now have multiple interviews spread over weeks, last time I did a job search it was usually a 1 hour screening interview/test followed up by half a day of interviews, but now 1h interview, then submit availability, then another 1h and so on, and you end up spending 4 weeks doing what you used to do in a day.

I don't understand how this is better than having the interviews in a single day, is it because of the volume of applicants this time around? or was it always like this but I got lucky before?