Your advice is in direct contradiction to common wisdom on career path building and offer negotiation because:
1. Even though you may be able to get a 50% more offer somewhere else, your value to your current employer (note not perspective employer) is mostly determined by your contribution to the team and comparable peers at your team/position in the company. Your market value was already considered when you first offered/joined the company, after that it's usually not a major factor to determine how you worth.
2. Your many short term tenure employments and the tendencies to job hopping is a STRONG bad sign for the long term health of your career development. And it deters future employees. It may be fine to be a junior engineer to hop jobs frequently BUT it's really hard to move up the ladder to management. More importantly, it shows that you have no loyalty to any single past employers and will not willing to invest in a long term career development track to rise up (with a few exceptions). For example, I was told anecdotally that BridgeWater Associates would not consider anyone who hops more than 3 jobs in a ten year period.
3. You rarely accrue long vacation where most companies offer that based on tenure, again with a few exceptions (companies with unlimited vacation days policies).
4. You have to build up personal relationships with a new team every other year (assuming you job hop less than 2 years in every job.) Trust me, your personal relationships with your close teammates is a big factor in job satisfaction. Meeting new people new team every other year could be cumbersome and tiring. This matters if you are aiming for a long term career development.
5. Less than two years of employment might not be long enough to really build up your values. According to Jesse Watson[1], as a software engineer, your value really lies in "the synthesis of programming skill and deep context in the business problem domain, in one skull." And it's unfortunate that less than 2 years does not strengthen that synthesis one skill but rather makes your more vulnerable to be replaced by outsourcing as a commodity monkey coder.
I used to work for TheLadders.com first job out of college and gained a lot of insights because of that. And I am very thankful for the valuable advices my former colleagues gave me. Although I job hopped a lot when I was a junior engineer but not anymore given all the reasons above.
So next time when you are at the crossroad for a switch, make sure you truly understand the consequences of pros and cons. And be sure to ask yourself, is my career development ready and worthy for short term 50% bump?
[1]: https://www.linkedin.com/pulse/hard-thing-software-developme...