I know that the usage of 仕方がない has been discussed here, but I had an additional question. If you say:

X (affirmative) より仕方がない

The translation as I understand it is that you have no other choice but to do X.

However, is another way to think about this grammar as:

X (negative) は仕方がある

or would this sentence have a different meaning than the former? As an example from my textbook, could I change the following:

車がないから、歩いて行くより仕方がない ー＞

 

車がないから、歩いて行かないのは仕方がある。

Finally, is it implied that the subject of the sentence with the は particle is being excluded as the option that is wanted?

I know that the usage of 仕方がない has been discussed here, but I had an additional question. If you say:

X (affirmative) より仕方がない

The translation as I understand it is that you have no other choice but to do X.

However, is another way to think about this grammar as:

X (negative) は仕方がある

or would this sentence have a different meaning than the former? As an example from my textbook, could I change the following:

車がないから、歩いて行くより仕方がない ー＞

車がないから、歩いて行かないのは仕方がある。

Finally, is it implied that the subject of the sentence with the は particle is being excluded as the option that is wanted?