Most alts are directly affected by the run-up in Bitcoin and hence are likely in bubbles as well (and in some cases even more-so than Bitcoin, in others less-so). In the ideal case where we see cryptocurrencies become real competitors in the world, then likely the ones that have been tested and are successful products will have a much higher chance of survival than the many projects that are just ideas or very low adoption. Hence why it is critical not to invest much the lower you go in the list.