I don't disagree with what you have said but it isn't just a question of the tax deferral from contribution to withdrawal.  Rather, it is a question of whether the value of the tax deferral in your earning years will match or exceed the value of tax paid upon withdrawal.  Which of course is dependent upon your marginal tax rate and the types of investments held within your RRSP.

In days of double digit interest rates the RRSP account provided many if not most investors with solid tax advantages.  With greater reliance on eligible dividends and capital gains today investors need to carefully evaluate their RRSP account in terms of both contributions as well as types of holdings to avoid paying excessive tax in retirement.  Which ultimately means using your RRSP strategically alongside the TFSA, Cash, and even RESP accounts.

Used properly the RRSP refund can in fact add to your post tax net worth.