It's very uncertain for an Altcoin to overcome Bitcoin.
Bitcoin dominance in the Crypto market is very influential for Atletico and greater control. Bitcoin which is the largest crypto asset by market capitalization can influence other coins to move in the same pattern, when Bitcoin goes up, other Altcoins tend to increase, when Bitcoin goes down, there is a possibility that other coins will go down at the same time. Another reason that makes it impossible for Altcoin to beat Bitcoin is because Bitcoin is the mother of all Cryptocurrencies, although some Altcoins try to imitate Bitcoin such as Litecoin which uses a copy of the Bitcoin code with the aim of being a lighter and faster version of the original, but this cannot have a big impact and Bitcoin still maintains its position. Bitcoin Cash, Bitcoin Gold, Bitcoin Diamond are also unable to beat the market capitalization that Bitcoin has achieved.
There is a big trust on bitcoin and its community which makes more people to rely and believe in bitcoin than altcoins. If you look from the creation of bitcoin, after several attacks from government, media and others, bitcoin was able to survive and grow in all these critics to this level, because it's beyond government control due to its decentralized nature. Furthermore, those investors that have invested in bitcoin since cteation till date has never been disappointed for hodli their bitcoin because the value has increased drastically and it is also a hedge to inflation. No altcoin has these qualities, most of time remain on the same price for over four years, with only a little difference in price addition.