That said garden leave is not all sunshine and roses like OP describes. It’s common on Wall Street but a huge part of your normal compensation is performance bonuses - and typically garden leaves only cover base salary.
A typical garden leave doesn’t come close to full income replacement for the period. But it’s better than nothing - which is the status quo in tech.
FWIW American courts also tend to frown on non competes that do not compensate for forced unemployment and have generally sided with the worker. This is (yet another) way that employers deprive employees of their rights by using the expense of litigation against them. This is also why we need regulation around this - you should not have to fight this in court to have your basic rights asserted.
Even severance is usually not much. Typical is one week for year of service, minimum two weeks.
Given turnover in the industry, very few people are going to get 20 weeks severance.
People in this thread are saying you "only" get your base. If they really do get full base pay of 200k, that puts them in the 94th percentile to take a forced vacation.