Well, the only thing we have as data from the topic is "low cap", which means that it doesn't state if we are talking about a new one or an old one, as long as it's a low cap one that fits the bill for what OP is talking about. However, when we think about a low cap one, we think about having something that is a bit more different, something that would be a bit more hardcore, and it will not be all that increasingly difficult neither.
If you check out Binance and kucoin exchange announcement channel then you will find that 90% tokens which exchange delist are low cap cois. SNM, SRM, YFII, QLC, NEBL and AUTO tokens has delisted and all are old coins. These coins was very volatile due to low cap and traders loves to select low cap coins for daily trading due to its high volatility in price. There are some low cap coins (fan coins) which has very low trading volume and taking lot of time in price increase.
I understand that it may not be all that great or anything like that, but we need to realize that old ones who are still low cap do not look that good. If you have been around for a while and haven't gone up, then what could make you go up? I do not think that they look like they are good for investment. New ones however, may still carry a huge risk when you invest into them, but that doesn't mean that you are going to end up with a profit at all, it just means that you are going to have at least some chance to make that profit.
Risk in low cap coins is higher than other coins wheather new ones old. Most of the time people enter in fomo and its took lot of time to get back to that price again. low cap coins are more unpredictable than other coins which generally depends upon btc price while low cap coins could increase 5x in bear market while sometimes only decreasing even in bull market.