I mean, that's one customer service rep who was being difficult (not necessarily representative of Adobe policy at all), and the user was trying to cancel a yearly subscription on the 365th day when it was already being charged for autorenewal that day.
That's not even remotely representative of someone who signs up for a monthly subscription and then cancels it before the month is up. But yes, obviously you have to put it in your calendar to remember to cancel it. It's not that hard.
There are complaints about everything all over the internet.
In my experience, I've never once had a problem cancelling SaaS. There will always be bad actors out there, and maybe Adobe has been one, and maybe they still are, but on the whole I haven't found SaaS to be any worse than anything else.
And it's not really where the economic incentives lie -- someone who is cancelling is someone who is likely to sign up again in the future, so it's generally not in a business's best interests to piss them off.
That's not even remotely representative of someone who signs up for a monthly subscription and then cancels it before the month is up. But yes, obviously you have to put it in your calendar to remember to cancel it. It's not that hard.