I don't think all alts are scams. A really interesting thought experiment on the necessity of alts was this. It centred around the creation of incentives. One argument is that all these alts could be done on either Eth or Btc in future so why create your own projects. Its because of the incentive structure. If you are successful launching on a parent coin you will probably register a tiny blip in terms of value increase. Launching your own coin incentivises a team to drive new innovation because of the potential for the price to appreciate. Driving innovation that otherwise wouldnt exist. Money talks