They don't need to, but they do lose a bunch more of the 'feeder' market. If need to edit video to a semi professional standard I'd pick this bundle at 12.99/month (and get extra tools i might need) vs adobe premiere for 22.99/month.

As someone who came up along side adobe, the only reason photoshop is as entrenched as it is is simply because of piracy. Ditto for premiere. It created the market that they then locked down with subscriptions.

I think you are going to see shops that are smaller, doing their own design stuff internally, increasingly moving away from adobe subscriptions.