What you're describing already happened twenty years ago. Konami patented beatmania's keysounding[0] and DDR[1]'s control scheme and effectively had veto rights on competing rhythm games for decades. And they enforced those rights very strictly:

- They sued Andamiro for Pump it Up, a competing dance game with five panels arranged diagonally. Andamiro was able to settle with Konami, possibly because they'd found some prior art that limited the DDR patent, which is the only reason why we still have PIU today.

- They sued RoXoR for In The Groove, a proprietary[2] fork of StepMania, which is a DDR clone. In The Groove was designed as a conversion kit for DDR cabinets as well as having dedicabs produced by Andamiro and then themselves. RoXoR settled and Konami basically got to kill ITG as part of the settlement.

- They sued Pentavision for having keysounding in DJMAX, a competing DJ game that was popular in Korea. They settled with the end result being that Konami gets a permanent share of DJMAX sales and Japanese distribution rights for that game.

- They sued AmuseWorld for EZ2DJ, although to be fair this one looks literally identical to five-key beatmania. They... sort of just rebranded to EZ2AC and kept going, as far as I can tell from the Wikipedia page?

Harmonix was involved with the ITG lawsuits at one point, so they wound up designing a more complicated and worse design-around for the keysounding patent in Guitar Hero. Other rhythm games not made by Konami also tend to have very generic keysounds (e.g. it just plays one sample).

As for extracting rent... oh boy. There's a reason why rhythm games disappeared from American and European arcades. To explain that I first need to provide some context. The ownership model that western arcade operators are used to is that they buy a very expensive machine (in the $10k+ range) and then get to rent it out to people for $1 a play or so. This is why private collectors and retro arcades exist and used to be how rhythm games worked too.

Konami changed all this in Japan over two decades ago. First they added online capability with eAmusement - you could pay a monthly fee to get your arcade cabinets auto-updated. Then they added score tracking through NFC cards through the same service. Around 2011 they switched to a licensing model where arcade owners have to pre-pay a rev share for each play, and as part of this, the machines have always-online DRM. If your machine isn't connected to Konami's eAmusement VPN, it won't boot, and if your revshare isn't paid up it won't accept payment from users.

Outside of East Asia, arcade operators balked at all of this. Originally this just meant not having eAmusement passes to save scores on, but after they moved to licensing instead of ownership, we stopped getting DDR cabinets altogether. Dave & Busters still wanted to operate DDR though, so they somehow got Round1[3] to negotiate a joint order of DDR White Cabs running a special build of DDR A with an offline mode. You're probably reading this and thinking that D&B is the good guy, except my local Round1's arcade techs hate them for this, because major game updates are now expensive upgrade kits that frequently brick machines[4]. Furthermore, D&B is penny-pinching right now, so the A3 upgrade for all the NA-region DDR cabs got delayed by like a year while Round1 renegotiated with Konami.

If you're not D&B or Round1, you either operate decades-old DDR cabinets, Pump It Up[5], or StepManiaX, another dance game by the ITG people with better patent design-arounds.

[0] When you press a button, the game makes the sound. It's why you know immediately when you suck at Beatmania.

[1] DanceDanceRevolution, not East Germany. (Formerly?) Known as "Dancing Stage" in Europe for this reason.

[2] They convinced StepMania's developers to relicense to MIT so they could license songs for ITG

[3] Round1 is an arcade chain from Osaka with a US branch and a frightening ability to get Konami to license import cabs for the US. It is the closest you'll get to the Japanese arcade experience in the US and you could probably film a shot-for-shot recreation of Lost in Translation in there.

[4] https://twitter.com/EvilDave219/status/1691599463276564579

[5] I have no clue if Andamiro's also charges revshare and requires always-online but I suspect they are.