I think the projects are somewhat responsible for this dump. After listing done, the development tends to slow down, innovations hardly come by. In fact good projects fall victim to this scenarios as well since people assume this is just another one of those. But I do agree with your idea of integrating bitcoin and/or ethereum. This way a good amount of investment can be made which could be beneficial to the respective coins.

Litecoin has some amazing features and thus attracted people immensely It's hard to predict the exact future. Ethereum and Litecoin share significant portion of the crypto market and both are in competetion with each other. I think the better will come out victorious.

You can visit the blockchain website in this matter. But if you want to get the exact numbers there are other platforms that can be used.

i do not think so if you find anyone who has paid their mortgages through bitcoin. Btw are you aware of the fact that mortgages allow cryptos anywhere? Mortgages involves banks most of the cases and crypto and banks live on the polar opposites.

High usage does not always mean that it is rated high. A lot of scam projects were built on the waves platform and this may be the reason why it is ranked so low.