Bitcoin's growth began in early 2017 and then it touch 20000. Bitcoin's largest growth is due to the ability to trade with tether dollar. With this growth, a huge growth in ICOs appeared. Nowadays about 30 ICOs are added to the market. This huge volume of ICOs, has taken the power of bitcoin growth. Like weeds next to a tree. Bitcoin will not grow until ICOs exists.
Your point of view is right and i think this is all because of the rise in demand of Altcoins in this cryptocurrency market as there is always new ICO's are releasing each new day and this new release of new altcoins are the major reason for decreasing of Bitcoin's growth in today's market. The huge volume of ICO's are affecting the growth and development of Bitcoin and because of this bitcoin is not expected to reach 20k price level in a easy fashion.