The only reason that Starmer and Reeves have now announced they are thinking about lifting the cap is because of a growing rebellion in the ranks. In fact, it's the sub in the article you linked to:
PM endorses earlier comments by Bridget Phillipson amid brewing rebellion on policy among Labour MPs
If a majority of Labour backbenchers had really wanted to get rid of the cap and said they would vote for the SNP amendment, you can bet that Starmer would have promised to lift the cap immediately in order to head off the rebellion, rather than just reviewing it
The only reason that Starmer and Reeves have now announced they are thinking about lifting the cap is because of a growing rebellion in the ranks. In fact, it's the sub in the article you linked to:
If a majority of Labour backbenchers had really wanted to get rid of the cap and said they would vote for the SNP amendment, you can bet that Starmer would have promised to lift the cap immediately in order to head off the rebellion, rather than just reviewing it