Polygon is currently ranked #19 in terms of Market Cap ($12,983,552,779) while Ethereum is ranked #2 ($568,895,777,058). Although MATIC has way more circulating supply, I still think it has plenty of growth to inch closer to its counterpart (Ethereum) in market cap and go up in price.
Aside from tokens like Polygon which actually improve existing blockchains, I think the best long term investments are in the blockchains themselves since that's the technology that I believe most everyone will be using in the future. Don't put long term money into tokens that don't have any purpose like DOGE & SHIB. Put long term money into tokens like MATIC that improve an existing blockchain or the blockchains themselves like ETH, ALGO and ADA.