By having bigger block size wouldn't they fix the issues of speed and scalability...
yes it will fix it but only temporarily.
No, not temporarily. Permanently. The maximum number of transactions is limited: it is number of people and organizations on Earth (limited) times the number of transactions they do in 10 minutes (limited). So the space needed to accommodate that number of transactions (aka block size) is limited too.
I learned recently (here on a different post answered) that are concerns of decentralization as a result of larger block. What if somebody could solve the concerns of decentralization in a larger block? How valuable this will be?
there is a much better solution and that I called
second layer which is basically what you keep hearing as Lightning Network.
People have doubts about Lightning Network. I am not taking sides here, but there is talk about high fees in the future and domination of LN by banks and corporations.
The onchain solution, on the other hand, doesn't have those doubts. I believe we must persevere until the time comes the disk space is cheaper and everybody can afford (if they choose so) to run a full node with blocks of
limited size, but larger than they are currently.