It actually is. Red Hook Studios created a single game (Darkest Dungeon), made bank, and is now working on a second. No MTX anywhere in sight. Larian Studios (Divinity Series) started with a small success, built on that, and are now on their... sixth game (I think)... Baldur's Gate 3. All done with no MTX. The story of CD Project Red is probably the most well known - famous for their refusal to use MTX. Witcher 1 - 3 and now Cyberpunk 2077 coming up.
Our current reality is one in which it is actually easier to create new computer games and get them to consumers than ever before thanks to online word of mouth and apps like Steam. Our current reality is one in which small, moderate, and even great success is being had without any MTX at all. MTX is only a part of our current reality, and is only there because consumers choose to support it. No other reason. It isn't essential to making a game. It isn't essential to making a sequel. And it certainly isn't essential to being successful.
Support it if you like it. Don't if you don't. But please don't be under the illusion that it's necessary to the development of decent games or franchises.