For starters, that is totally normal. The majority of viewers on YouTube do not subscribe to many channels. It may also take several videos to convince someone, and sometimes people don't even know how to subscribe (it's just no something that is important to them. The best thing you can do to convert them is to provide a LOT of value... make it so that it is a mistake if they do not subscribe to your channel. Of course provide your CTA's etc... but honestly that is far less important than providing value. CTA's are so prevalent that they often fall on deaf ears these days.
I would not mind getting more subs, but as long as my CTR, views, and retention are good, I do not worry about subs much.
I agree that a lot of viewers just do not subscribe to many channels. I have been on YT since 2006, I am on YT for way too many hours a day (I am gloriously retired ha ha)... but... I subscribe to just under 100 channels. And it is past time to clean out the list of channels I do not watch regularly. I watch a lot but there are very few genres I would bother subscribing to.
This really is a hard time to deal with, audience viewing without subscribing is such a pain in the ***. But I know for sure, as time goes on, they surely will get intouch with the CTA procedures, hearing most of them don't even know what is meant by sub. So it's a matter of time as a beginner. Am also facing the same problem though.
What Stanley said plus make sure you give them an incentive to subscribe. Try to find a way to mention to your viewers to like and subscribe but without coming off as annoying or demanding. Many of the videos I watch these days have invented creative ways to mix in reminders to subscribe with the content they create making it seem obvious but also seamless. Do some testing and figure where the request to subscribe works best for you. Try at the beginning, in the middle and towards the end of different videos (not all at the same time in every video) and see which ones tend to work best.
If you are under 1,000 subs I understand the frustration. The only real sub number that means anything is 1,000. Once you are monetized the sub count does not really give much, except an ego boost.
Your analytics are more important. Get your CTR and retention in good shape, and the algorithm will love you.