Honestly, let old software die. Time to upgrade your hardware
[Minor Rant]
"Old" does not equal "bad" or "ineffective" or "unusable". "Old" simply refers to chronological age.
If a set of hardware/software did the job perfectly 20 years ago, and it still does the same job perfectly today, why should you upgrade to some new thing to solve the same problem you already have solved nicely with your "old" hardware/software?
Honestly, ALL of my music (20+GB of it) has been ripped via iTunes, exists in my iTunes library and is routinely loaded onto my iPod Classic. That iPod Classic is the primary music source for our home - it is plugged in as an audio input to our amplifier and plays all the playlist, albums and singles that I want to listen to. It worked perfectly in 2006, and it still works perfectly today. I have of course been adding to the library, but other than that, it worked well then and it keeps working well now.
"Old" does not equal "obsolete".
Streaming music is a time bomb. If you don't possess the sound files, you don't really own the music and you can easily lose access to it at any time. You may have paid for it, but you only have access as long as there is a free and unfiltered Internet. If/when the Internet is disturbed, censored, filtered etc. (and governments around the world block the Internet or parts thereof with frightening frequency) you no longer have access to your music/videos/etc.
Purchasing the music, either via online download or via buying and ripping the original album/CD/etc. and then loading it onto a backed up physical device such as an iPod, works brilliantly, AND you own the music.
If your existing combination of [Older Mac/iTunes/iPod] solves your music storage, access and playback problems, why replace it with a more troublesome mechanism, and one that is subject to government oversight, ISP failures, etc.
It "ain't broke".... why fix it?
[/Minor Rant]