I don't agree with your third point. We may miss a good and potential startup up we ignore new project. If we invest in a good startup the profit we receive will much bigger than an old project. It's the truth in both crypto market and in real life. Smart investors prefer new good project than old project.
How can we know if the new project is better than the old project? while the old project has been developed first, in this case I think investors will also consider it, it's up to you whether you want to agree or not on the third point, because everyone has their own assessment for themselves.
If the definitions will be in terms of potential gains and it will be base in short time period maybe successful startups can provide decent than existing ones, but if the basis is stonger usable cause then for sure old coins that still exist and still moving forward is way back better investment than newer project, the long term support from communities brings the project to it's strong barrier.