Personally, I have a bit of a fond spot for "pay and that's it", but that model itself isn't perfect either.
Because, nowadays multiplayer is considered part of the experience - and in fact, the latest few major games to trend were all multiplayer heavy to some extent - which makes the "pay and that's it" model a bit inefficient, because multiplayer usually means servers, continuous dev time being used to identify and prevent cheating, a bigger concern on the balancing part of things (something that's balanced in single player won't necessarily be balanced on multiplayer and vice-versa).
So the online experience has a tendency to inflate costs which makes a subscription model be favorable to a lot of multiplayer games.
The thing with microtransactions is in part predatory business practices (much like a number of other industries, there are a small number of players that pay absurd amounts of money for those) and in part a market fit.
Due to being relatively easy to spoof reviews in mobile app stores / PC game stores and the relative lack of quality control in those same stores compared to regular consoles, there are a lot of duds or just generally crappy games in the platform, which means that in general people are less likely to pay for mobile games and that's why the freemium models have arrived - unless you can afford a big marketing campaign or have some sort of accolades and external approval, having a mobile game have the "pay once play forever" model is generally not a good financial decision.
Now, of course ads are a perfectly acceptable alternative to microtransactions - and is the one I prefer - perhaps with a "Pay X cash to get rid of ads forever" option.
And finally, I consider DLC to be a good thing in general. In the olden days, if you had some extra content or some new ideas related to a previous game you had, you had to either get enough to make a sequel, or you had to mostly repackage the original game with a few changes sprinkled in cough cough Pokemon cough cough.
DLCs allow creator to have more control about any extension of their work, while allowing a fairer price to players. While there are game shops that "abuse" this system, you'll have abuse in any payment model.
tl;dr:
- "Pay once play forever" is good for single player games on console
- Subscription models are good for multiplayer games on console
- Microtransactions are predatory and just generally bad
- Ads are nice freemium alternative for games that are not on console - preferrably with either previous option as a way to get rid of ads.
- DLC is a good way to extend games
