D+ works best as a one or two month a year sub compared to its competitors it certainly looks like.
In your case that is true. For me personally the reason I bought the year subscription is to have Disney, Pixar, MCU and Str Wars films whenever I want (and in 4K) all the original content is just an added bonus.
At the moment I have Netflix this month for Witcher which I've just seen the first episode of and it is great and some of their films like MarriageStory which was also great, I'll get rid of it til March once it lapses and then watch Kingdom and cancel it again.
It could be because I'm in New Zealand but Netflix doesn't have much great acquired content and their originals don't really lend themselves to re-watches in my opinion, so no point in my having it year round, I also get Prime Video and Animelab once or twice a year to catch up on their content could possibly do the same with Apple TV+ if they put out some great stuff.
This is a much longer retort than what I thought it would be but I really think each people will choose streaming services and how much they keep them throughout the year depending on personal tastes so saying the Disney+ lacks value compared to its competitors I think is overall untrue (it's cheaper, has 4K support and has a lot of high quality films and some great shows with a steady stream of originals coming) but maybe it's just true in your case as someone that purely wants to watch their original content. That's all fine but from the polls that have been done we know most people mainly watch their catalogue content.
I'm sure most of these streaming services will be successful and reach the audiences they are targeting and those that fail will merge with bigger players so it won't be much of a lose to the subscribers overall.