Yes sometimes it’s a dollar or two and it really adds up quick. Sometimes 10’s of dollars. That door speaker can be few dollars cheap - you may get 2% more THD in a frequency band… the conversations can be really reduced down to ‘meh subjectively not noticeable’ but will save us a million.
Add few of these things and now you have a shitty radio system but 5 mil in bank.
Speakers are a bit of a funny one, because, with the important condition that the amp needs to not be crap, they’re pretty straightforward to upgrade for the end user.