I'd love a website I could enter my account info for these streaming sites and turn each one on, one month at a time, with a click of a button. This would attract the ire of streaming companies though.
This would be a fun idea. Especially if this was combined with your watchlist. The website could decide you have most stuff on your wishlist for service X, automatically cancel/subscribe, and send you an e-mail with a summary of what you can watch in the upcoming month.
This is what Plex has branched into, kinda, although there's no automatic subscription management since no service wants to give up control of cancellations and whatnot.
Realistically it’s already very easy to do this. Sure it’s not one click, but it takes all of 30 seconds.
The DoNotPay app does that. You can make a card for a specific account or trial and share account access through it too.