In a lot of my own films I’ve made, using Creative Commons Music also known as Royalty free have been very usual when look for top quality soundtrack / music, it’s a website where you can share and use composers work without payment and often without being mentioned in the credit roll. However, this depends on the composer.
I use bensound.com and most of is his work is downloadable for free and some other songs have a different licensing fee. The website, bensound.com charge based of the license types. For example, it’s $22 USD (£15) for song usage on online videos compared to National Television which is $720 USD (£505) Having access to music was very useful as there are many website with different genres with the option to download soundtracks made by other people for your own content.
There are some composers that watermark their work by subtlety mention the name of their company in the soundtrack which you can’t edit out or the composer has other instructions for the producer like being mentioned in the credits.
If there was a strict copyright law, I feel like independent film makers and content creators would struggle accessing top quality soundtracks/ music. The advantage is that these composers are paid for the usage of the soundtrack but for the users, there are more limitations. For example, if you were on a tight budget and couldn’t hire a music composer, royalty free music would be something to rely on- It wouldn’t be possible if there is tighter copyright control.