There are aspects that make bitcoin users more and more convinced that bitcoin is a good place for investment so now bitcoin prices are rising in the market!
Bitcoin's price is going strong, but not as strong as the alts in the market. Altcoins' price are shooting through the roof. It doesn't matter which alt you pick. Most of them have given phenomenal gains in the last 2 months.
Im not sure Id agree with you, it seems like btc is whats driving altcoin prices, not the other way around. Take a look at any price chart over time of the stable altcoins, not just the BS ones that shoot up in value really fast and depreciate over the next couple weeks.
Long term, most of them keep rough pace with BTC. At this point, Bitcoin has become like an index fund for cryptocurrency, reasonably stable compared to its alternatives, and a good overall indicator of the whole market.