I used to think scalability is an issue. I even asked questions, didn't get the right answer or got ignored. lol.
But later came into understanding that scalability is a gradual process. It is not necessarily the question of "can you scale or not". But rather when such measures become necessary.

For example you start a hotel business. You expect to have 20 guests next year. Would you buy or build a hotel with 400 rooms or 40 rooms?

Similarly, there is no need to take any drastic measures until certain amount of transactions start happening on daily basis. Sudden increase would signal devs and witnesses, ok it is time to do something.
And they do have ideas to what to do and how to react to such situations, I think.

One of the measures could be increasing a block size. Then work on something even more sophisticated.

It just has to do with time and resources that need to be spent. Because in addition to the blockchain data there is images infrastructure that requires a lot resources too.

There are many things to consider, but most I think are already considered. When the time comes devs will be ready.