An H-1B worker can take there H-1B and go to any company they want, as often as they want. There is competition in their wages.
L1 Vida holders are trapped at their company, unless another company will sponsor a new H-1B.
I can't find any information on how many active L1s there are now, and they are unlimited.
These could be impacting salaries dramatically.
Many different kinds of work visa programs should be ended or cut back drastically, including visas for lower-wage seasonal jobs.
Up to 20-25 years ago, you could still find an entry level job and work your way up.
Now, most of those jobs are gone. Many jobs have gone to other countries. Many other jobs have been automated.
Meanwhile, many jobs in this country are filled by foreign workers here on temporary visas.