Stiff-stemmed Herbs get their yummy fragrances from oils they exude, so I’m thinking two things may have happened; too much watering and not enough (if any) fertilizing.
The herbs you listed like it hot and dry, so I would use a slow-release fertilizer in the soil (like an Osmocote-brand formula 14-14-14) and be sparing on the watering, meaning let them dry out thoroughly before watering again.
Of course, there’s not a thing you can do about how much or how little it rains. ;)
Thank you. I’ll do as you suggest and fertilize!