Late 40s not young, not old. Retirement age now at 62 will likely be pushed up to 65. So plenty of time to continue to build up your nest egg.

Don't hope, but rather work towards your goal. If you have only 1 property and you are staying in it, any price appreciation will not really give you the cash flow you need in your retirement. You will be in an asset rich cash poor situation. Try and gun for an investment property. That way, you can derive rental income and still see the asset appreciating.

If both you and spouse are degree holders in executive positions, chances of your net worth growing to $4m and and above when in your 50s are high. This projection or trajectory is quite typical of professional couples who stayed in their jobs till retirement at 55 or later.