It depends on the project if the project is promising than investing in that will be better option than buying old tokens.
But, how can we know that the new project is promising? There are so many ways for them to fake it and not all of us have the knowledge to detect it but for the old projects, we are already sure about their ability or on what they can do and that is why they are still the best. If we can't help it then invest only small amount on new coins but make the most of your investment in the old coins so that whatever happens on that new coin, you won't regret it heavily.
Is it true that new altcoins are the best to invest in right now? Someone said you can easily make better profits from new projects than investing in old altcoins that have already x their values already, what do you think? Good or bad idea.
Right now that we are in a bear? No. it's rare to see a new project being released right now because the devs also know that they can't get much hype. When we are in a bull, that might be true but only if you get lucky but you should also know when to quit because the return of that quick profit can also be a quick losses.