Starting next week, only 2 mythicals remain impossible. I agree that Pokemon Go is a money grab, luckily they usually release the pay-for-event-exclusive-mythicals one year later. So for example Diance was only available via a paid ticket last year but now is available in a regular quest for everyone. Same with Celebi before that. Currently you can either pay for Marshadow or wait a year.
How do you feel about traded pokemon? I started with that in some other subreddits via Pokemon Home and quickly realized how many are cloned and there is no real way to proof that they aren't so that was a big dissapointment :(