According to a recent report from Collider, it seems that maybe Disney could be considering it. It would seem that there have been some layoffs from both Hulu and Disney+ in anticipation of such a move because of overlapping positions. This means that maybe Disney could already be getting ready for such a merger between Hulu and Disney+.
A Hulu spokesperson has denied the report, claiming that this is just hypothetical speculation and that there are no such plans at the moment. However, it does make sense that Disney could want to combine its various services together to create one giant catalogue of shows. This would make the service a lot more attractive compared to other platforms, plus it sounds a lot better on paper where Disney could announce that they have over 100 million subscribers, instead of 70 million or so on Disney+ and 30 million or so on Hulu.
That being said, there might be a reason Disney has not done it yet. Hulu and Disney+ both cater to a different set of audiences, so maybe the company is trying to grow both services at the same time. Either way, take it with a grain of salt for now.