It has been seen in Gran Turismo 7 that there are no rental cars (cars that you can use for free) in the Arcade Modes (Arcade Race, Time Trial and Custom Race). Furthermore, there are only 13 rental cars in the offline mode and two-player battle modes.

This promotes excessive, tedious grinding, sometimes even the use of optional microtransactions, and that cars in the game are either overpriced, and as of version 1.07, it is even harder to earn credits as they reduced the payments for completing certain events. Furthermore, certain cars are time-limited, such as invite-only cars in Brand Central, and those sold in the Used and Legendary Car Dealerships.

For reference, Gran Turismo 4's Arcade Mode lets you start off with 240 rental cars, then you go off to unlock the rest (719 cars in the North American version) in the campaign mode (obtaining a car at least once unlocks it permanently as a rental car, with all their available colors/liveries to select from).

While we already have the option to use cars from our garage in the Arcade Modes, which is essential, the fact that Polyphony has continued this trend of only including a handful of rental cars in favor of a grind-heavy economy, needs to change.

The Arcade Modes need to redefine free play, as well as the concept of "more fun, less grind".

Here are some solutions that Polyphony can implement in a future update to Gran Turismo 7:

• Implement all cars in the game as rental cars in Arcade Races, Time Trials, Custom Races, 2-Player Battles and the offline mode right away. 
• Implement a system similar to Gran Turismo 4 where obtaining a car at least once will unlock it permanently as a rental car in Arcade Races, Time Trials, Custom Races, 2-Player Battles and the offline mode, where eventually all the cars in the game will become available for use once all have been collected.

In Custom Races, besides "Select from Garage", there should be a "Select Cars Individually" feature that allows us to handpick the AI opponents' cars based on rental cars.

Pros:

• Allows players to try cars before they buy them, a deciding factor that will help them in getting these cars in the Campaign mode
• Allows for quick experimentation between other cars, and also to enhance players' skills as they're able to drive more unique cars
• It also allows players to just jump in and choose whatever car they like, either if they want to just play casually or take a break from the campaign mode
• Rental cars in the Arcade Modes will not go through oil, engine and chassis rigidity degradation
• The game is mostly played online, so if all the cars in the game are available in the offline mode as rental cars, those who wish to play offline can still get to drive whatever they want

Cons/restrictions:

• You can only select car-specific default colors, variations and liveries, and you cannot customize and/or upgrade them
• Set-up tuning will be car-specific, based on the default tune (stock). You can use any tire compound you want, though.
• Credits and Daily Workout progress will not be earned driving a rental car, as opposed to using cars from your Garage.
• Rental cars cannot be used outside of the mentioned game modes. You'll have to buy them if you want to use them in the campaign.

*NOTE: We should still also have the ability to use cars from our campaign garage too.